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  • Kinetics  (75)
  • American Association for the Advancement of Science (AAAS)  (75)
  • American Chemical Society
  • Periodicals Archive Online (PAO)
  • 1985-1989  (75)
  • 1980-1984
  • 1965-1969
  • 1988  (49)
  • 1986  (26)
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  • American Association for the Advancement of Science (AAAS)  (75)
  • American Chemical Society
  • Periodicals Archive Online (PAO)
  • Springer  (8)
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  • 1985-1989  (75)
  • 1980-1984
  • 1965-1969
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  • 1
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-11-25
    Description: The human immunodeficiency virus type 1 (HIV-1) shows extensive genetic variation and undergoes rapid evolution. The fidelity of purified HIV-1 reverse transcriptase was measured during DNA polymerization in vitro by means of three different assays. Reverse transcriptase from HIV-1 introduced base-substitution errors in DNA from the bacteriophage phi X174 amber3 at estimated frequencies of 1/2000 to 1/4000. Analyses of misincorporation rates opposite a single template adenine residue showed that HIV-1 reverse transcriptase catalyzed nucleotide mismatches with a specificity of A:C much greater than A:G greater than A:A. The high error rate of HIV-1 reverse transcriptase in vitro translates to approximately five to ten errors per HIV-1 genome per round of replication in vivo. This high error rate suggests that misincorporation by HIV-1 reverse transcriptase is, at least in part, responsible for the hypermutability of the AIDS virus. The specificity of misincorporation may provide a basis for the systematic construction of antiviral nucleosides.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Preston, B D -- Poiesz, B J -- Loeb, L A -- CA-07263-03/CA/NCI NIH HHS/ -- N01AI72654/AI/NIAID NIH HHS/ -- R35-CA-39903/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Nov 25;242(4882):1168-71.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2460924" target="_blank"〉PubMed〈/a〉
    Keywords: Avian Myeloblastosis Virus/enzymology ; Bacteriophage phi X 174/genetics ; DNA/*biosynthesis ; DNA Polymerase II/metabolism ; DNA, Viral/biosynthesis ; Electrophoresis, Polyacrylamide Gel ; HIV/*enzymology/genetics ; Kinetics ; Moloney murine leukemia virus/enzymology ; Mutation ; Nucleotides/metabolism ; RNA-Directed DNA Polymerase/*metabolism
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  • 2
    Publication Date: 1988-04-22
    Description: BC3H1 myocytes release membrane-bound alkaline phosphatase to the incubation medium upon stimulation with insulin, following a time course that is consistent with the generation of dimyristoylglycerol and the appearance of a putative insulin mediator in the extracellular medium. The use of specific blocking agents shows, however, that alkaline phosphatase release and dimyristoylglycerol production are independent processes and that the blockade of either event inhibits the production of insulin mediator. These experiments suggest a new model of insulin action.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Romero, G -- Luttrell, L -- Rogol, A -- Zeller, K -- Hewlett, E -- Larner, J -- AI 18000/AI/NIAID NIH HHS/ -- AM 14334/AM/NIADDK NIH HHS/ -- AM 22125/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 22;240(4851):509-11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University of Virginia School of Medicine, Charlottesville 22908.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3282305" target="_blank"〉PubMed〈/a〉
    Keywords: Alkaline Phosphatase/metabolism/secretion ; Animals ; Diglycerides/metabolism ; Enzyme Activation/drug effects ; Extracellular Space/enzymology ; Glycolipids/*physiology ; In Vitro Techniques ; Insulin/*pharmacology ; Kinetics ; Membrane Glycoproteins/*physiology ; Phosphatidylinositols/*physiology ; Pyruvate Dehydrogenase Complex/metabolism
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  • 3
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-11-04
    Description: The anticodon has previously been shown to play a role in recognition of certain transfer RNAs by aminoacyl-tRNA synthetases; however, the extent to which this sequence dictates tRNA identity is generally unknown. To investigate the contribution of the anticodon to the identity of Escherichia coli methionine and valine tRNAs, in vitro transcripts of these tRNAs were prepared that contained normal and interchanged anticodon sequences. Transcripts containing wild-type tRNA sequences were excellent substrates for their respective cognate aminoacyl-tRNA synthetases and were effectively discriminated against by a variety of noncognate enzymes. The mutant tRNAs produced by switching the anticodon sequences lost their original tRNA identity and assumed an identity corresponding to the acquired anticodon sequence. These results indicate that the anticodon contains sufficient information to distinguish methionine and valine tRNAs with high fidelity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schulman, L H -- Pelka, H -- New York, N.Y. -- Science. 1988 Nov 4;242(4879):765-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Developmental Biology and Cancer, Albert Einstein College of Medicine, Bronx, New York 10461.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3055296" target="_blank"〉PubMed〈/a〉
    Keywords: *Anticodon ; Escherichia coli ; Kinetics ; Methionine-tRNA Ligase/metabolism ; *RNA, Transfer ; RNA, Transfer, Amino Acid-Specific/*physiology ; RNA, Transfer, Met/*physiology ; RNA, Transfer, Val/*physiology ; Substrate Specificity ; *Transfer RNA Aminoacylation ; Valine-tRNA Ligase/metabolism
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  • 4
    Publication Date: 1988-11-25
    Description: A cell-free translation system has been constructed that uses a continuous flow of the feeding buffer [including amino acids, adenosine triphosphate (ATP), and guanosine triphosphate (GTP)] through the reaction mixture and a continuous removal of a polypeptide product. Both prokaryotic (Escherichia coli) and eukaryotic (wheat embryos, Triticum sp.) versions of the system have been tested. In both cases the system has proven active for long times, synthesizing polypeptides at a high constant rate for tens of hours. With the use of MS2 phage RNA or brome mosaic virus RNA 4 as templates, 100 copies of viral coat proteins per RNA were synthesized for 20 hours in the prokaryotic or eukaryotic system, respectively. With synthetic calcitonin messenger RNA, 150 to 300 copies of calcitonin polypeptide were produced per messenger RNA in both types of continuous translation systems for 40 hours.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Spirin, A S -- Baranov, V I -- Ryabova, L A -- Ovodov, S Y -- Alakhov, Y B -- New York, N.Y. -- Science. 1988 Nov 25;242(4882):1162-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Protein Research, Academy of Sciences, Moscow Region, USSR.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3055301" target="_blank"〉PubMed〈/a〉
    Keywords: Bacteriophages/genetics ; Calcitonin/biosynthesis/genetics ; Capsid/biosynthesis/genetics ; Electrophoresis ; Escherichia coli/*metabolism ; Kinetics ; Mosaic Viruses/genetics ; *Peptide Biosynthesis ; Plants/*metabolism ; *Protein Biosynthesis ; RNA, Messenger/metabolism ; RNA, Viral/genetics ; Ribosomes/metabolism ; Templates, Genetic ; Triticum
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  • 5
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-01-08
    Description: The Bacillus subtilis ribonuclease P consists of a protein and an RNA. At high ionic strength the reaction is protein-independent; the RNA alone is capable of cleaving precursor transfer RNA, but the turnover is slow. Kinetic analyses show that high salt concentrations facilitate substrate binding in the absence of the protein, probably by decreasing the repulsion between the polyanionic enzyme and substrate RNAs, and also slow product release and enzyme turnover. It is proposed that the ribonuclease P protein, which is small and basic, provides a local pool of counter-ions that facilitates substrate binding without interfering with rapid product release.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reich, C -- Olsen, G J -- Pace, B -- Pace, N R -- GM34527/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jan 8;239(4836):178-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Indiana University, Bloomington 47405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3122322" target="_blank"〉PubMed〈/a〉
    Keywords: Bacillus subtilis/*enzymology ; Endoribonucleases/*physiology ; Kinetics ; Nucleic Acid Precursors/metabolism ; RNA, Transfer/metabolism ; Ribonuclease P ; Ribonucleoproteins/*physiology ; Structure-Activity Relationship
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  • 6
    Publication Date: 1988-12-16
    Description: The fidelity of protein biosynthesis in any cell rests on the accuracy of aminoacylation of tRNA. The exquisite specificity of this reaction is critically dependent on the correct recognition of tRNA by aminoacyl-tRNA synthetases. It is shown here that the relative concentrations of a tRNA and its cognate aminoacyl-tRNA synthetase are normally well balanced and crucial for maintenance of accurate aminoacylation. When Escherichia coli Gln-tRNA synthetase is overproduced in vivo, it incorrectly acylates the supF amber suppressor tRNA(Tyr) with Gln. This effect is abolished when the intracellular concentration of the cognate tRNA(Gln2) is also elevate. These data indicate that the presence of aminoacyl-tRNA synthetase and the cognate tRNAs in complexed form, which requires the proper balance of the two macromolecules, is critical in maintaining the fidelity of protein biosynthesis. Thus, limits exist on the relative levels of tRNAs and aminoacyl-tRNA synthetases within a cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Swanson, R -- Hoben, P -- Sumner-Smith, M -- Uemura, H -- Watson, L -- Soll, D -- New York, N.Y. -- Science. 1988 Dec 16;242(4885):1548-51.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3144042" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acyl-tRNA Synthetases/genetics/*metabolism ; Escherichia coli/enzymology/*genetics ; Kinetics ; Plasmids ; RNA, Transfer, Amino Acid-Specific/*metabolism ; RNA, Transfer, Gln/*metabolism ; beta-Galactosidase/genetics/metabolism
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  • 7
    Publication Date: 1988-12-09
    Description: Potassium channels in neurons are linked by guanine nucleotide binding (G) proteins to numerous neurotransmitter receptors. The ability of Go, the predominant G protein in the brain, to stimulate potassium channels was tested in cell-free membrane patches of hippocampal pyramidal neurons. Four distinct types of potassium channels, which were otherwise quiescent, were activated by both isolated brain G0 and recombinant Go alpha. Hence brain Go can couple diverse brain potassium channels to neurotransmitter receptors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉VanDongen, A M -- Codina, J -- Olate, J -- Mattera, R -- Joho, R -- Birnbaumer, L -- Brown, A M -- DK-19318/DK/NIDDK NIH HHS/ -- HL-31154/HL/NHLBI NIH HHS/ -- HL-37044/HL/NHLBI NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1988 Dec 9;242(4884):1433-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3144040" target="_blank"〉PubMed〈/a〉
    Keywords: Adenylyl Imidodiphosphate/pharmacology ; Animals ; Cattle ; Electric Conductivity ; GTP-Binding Proteins/*pharmacology ; Hippocampus/*physiology ; In Vitro Techniques ; Kinetics ; Macromolecular Substances ; Membrane Potentials/drug effects ; Potassium Channels/drug effects/*physiology ; Pyramidal Tracts/physiology ; Rats ; Recombinant Proteins/*pharmacology
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  • 8
    Publication Date: 1988-06-10
    Description: Proteins undergo a series of nonenzymatic reactions with glucose over time to form advanced glycosylation end products (AGEs). Macrophages have a receptor that recognizes the AGE moiety and mediates the uptake and degradation of AGE proteins. This removal process is associated with the production and secretion of cachectin (tumor necrosis factor) and interleukin-1, two cytokines with diverse and seemingly paradoxical biological activities. The localized release and action of these cytokines could account for the coordinated removal and replacement of senescent extracellular matrix components in normal tissue homeostasis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vlassara, H -- Brownlee, M -- Manogue, K R -- Dinarello, C A -- Pasagian, A -- R01-AI15674/AI/NIAID NIH HHS/ -- R01-AM19655/AM/NIADDK NIH HHS/ -- R01-AM33861/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1546-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Medical Biochemistry, Rockefeller University, New York, NY 10021.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3259727" target="_blank"〉PubMed〈/a〉
    Keywords: Glycosylation ; Humans ; Interleukin-1/*biosynthesis/genetics ; Kinetics ; Membrane Glycoproteins/*physiology ; Monocytes/*metabolism ; Protein Biosynthesis ; RNA, Messenger/genetics ; Tumor Necrosis Factor-alpha/*biosynthesis/genetics
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-17
    Description: Biochemical and electrophysiological studies suggest that adenosine 3',5'-monophosphate (cAMP)-dependent phosphorylation of the nicotinic acetylcholine receptor channel is functionally significant because it modifies the receptor's rate of desensitization to acetylcholine. In studies that support this conclusion researchers have used forskolin to stimulate cAMP-dependent phosphorylation in intact muscle. It is now shown that although forskolin facilitated desensitization in voltage-clamped rat muscle, this effect was not correlated with the abilities of forskolin and forskolin analogs to activate adenylate cyclase or phosphorylate the receptor. Furthermore, elevation of intracellular cAMP or addition of the catalytic subunit of A-kinase failed to alter desensitization. Therefore, in intact skeletal muscle, cAMP-dependent phosphorylation does not modulate desensitization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wagoner, P K -- Pallotta, B S -- GM32211/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 17;240(4859):1655-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Pharmacology, Glaxo Research Laboratories, Chapel Hill, NC 27599.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2454507" target="_blank"〉PubMed〈/a〉
    Keywords: 1-Methyl-3-isobutylxanthine/pharmacology ; Acetylcholine/pharmacology ; Adenylyl Cyclases/metabolism ; Animals ; Bucladesine/pharmacology ; Colforsin/*pharmacology ; Cyclic AMP/analogs & derivatives/*pharmacology ; Electric Conductivity ; Enzyme Activation/drug effects ; Kinetics ; Muscles/*metabolism ; Phosphorylation ; Rats ; Receptors, Cholinergic/drug effects/*physiology ; Torpedo/metabolism
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  • 10
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-10-07
    Description: The enzymes adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase (protein kinase A) and protein kinase C regulate the activity of a diverse group of cellular proteins including membrane ion channel proteins. When protein kinase A was stimulated in cardiac ventricular myocytes with the membrane-soluble cAMP analog 8-chlorphenylthio cAMP (8-CPT cAMP), the amplitude of the delayed-rectifier potassium current (IK) doubled when recorded at 32 degrees C but was not affected at 22 degrees C. In contrast, modulation of the calcium current (ICa) by 8-CPT cAMP was independent of temperature with similar increases in ICa occurring at both temperatures. Stimulation of protein kinase C by phorbol 12,13-dibutyrate also enhanced IK in a temperature-dependent manner but failed to increase ICa at either temperature. Thus, cardiac delayed-rectifier potassium but not calcium channels are regulated by two distinct protein kinases in a similar temperature-dependent fashion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Walsh, K B -- Kass, R S -- New York, N.Y. -- Science. 1988 Oct 7;242(4875):67-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Rochester, School of Medicine and Dentistry, NY 14642.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2845575" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cyclic AMP/*analogs & derivatives/pharmacology ; Guinea Pigs ; Heart/*physiology ; Homeostasis ; In Vitro Techniques ; Kinetics ; Membrane Potentials ; Potassium Channels/*physiology ; Protein Kinase C/*metabolism ; Protein Kinases/*metabolism ; Thermodynamics ; Thionucleotides/*pharmacology ; Ventricular Function
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  • 11
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-12-16
    Description: The expression of a laboratory strain of HIV-1 (HTLV-IIIB) has been studied in mitogen-stimulated peripheral blood lymphocytes (PBLs) and in two lymphoid cell lines (CEM cells and C8166 cells). HIV-expressing cells contained from 300,000 to 2,500,000 copies of viral RNA per cell. Near-synchronous expression of an active infection could be achieved in C8166 cells. In these cells, the high copy numbers of viral RNA used as much as 40% of total protein synthesis for the production of viral gag protein, with high levels of viral RNA and protein synthesis preceding cell death by 2 to 4 days.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Somasundaran, M -- Robinson, H L -- AI 24474/AI/NIAID NIH HHS/ -- N01-HB-6-7022/HB/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Dec 16;242(4885):1554-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Massachusetts Medical Center, Worcester 01655.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3201245" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Line ; *Cell Transformation, Viral ; HIV-1/*genetics/growth & development/metabolism ; Humans ; Kinetics ; Lymphocytes/*microbiology ; RNA, Viral/*biosynthesis ; Viral Proteins/*biosynthesis
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  • 12
    Publication Date: 1988-03-18
    Description: The effects of lithium on inositol phosphate metabolism may account for the therapeutic actions of lithium in affective disorder. Muscarinic stimulation of the phosphoinositide system blocks synaptic inhibitory actions of adenosine in the hippocampal slice. At therapeutic concentrations, lithium diminished this muscarinic response, whereas rubidium, which does not affect phosphoinositide metabolism, had no effect. A dampening of phosphoinositide-mediated neurotransmission may explain the normalizing effects of lithium in treating both mania and depression.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Worley, P F -- Heller, W A -- Snyder, S H -- Baraban, J M -- DA-00266/DA/NIDA NIH HHS/ -- MH-18501/MH/NIMH NIH HHS/ -- MH-42323/MH/NIMH NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1988 Mar 18;239(4846):1428-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2831626" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine/pharmacology ; Carbachol/pharmacology ; Enzyme Activation/drug effects ; Hippocampus/drug effects/*physiology ; Inositol Phosphates/metabolism ; Kinetics ; Lithium/*pharmacology ; Oxotremorine/analogs & derivatives/pharmacology ; Phorbol Esters/pharmacology ; Phosphatidylinositols/*metabolism ; Protein Kinase C/metabolism ; Receptors, Muscarinic/drug effects/*physiology ; Synapses/physiology ; Synaptic Transmission/drug effects
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  • 13
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-06-24
    Description: A specific, reversible binding site for a free amino acid is detectable on the intron of the Tetrahymena self-splicing ribosomal precursor RNA. The site selects arginine among the natural amino acids, and prefers the L- to the D-amino acid. The dissociation constant is in the millimolar range, and amino acid binding is at or in the catalytic rG splicing substrate site. Occupation of the G site by L-arginine therefore inhibits splicing by inhibiting the binding of rG, without inhibition of later reactions in the splicing reaction sequence. Arginine binding specificity seems to be directed at the side chain and the guanidino radical, and the alpha-amino and carboxyl groups are dispensable for binding. The arginine site can be placed within the G site by structural homology, with consequent implications for RNA-amino acid interaction, for the origin of the genetic code, for control of RNA activities, and for further catalytic capabilities for RNA.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yarus, M -- R37 GM30881/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1751-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3381099" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arginine/*metabolism ; Binding Sites ; Catalysis ; Genetic Code ; Guanosine Triphosphate/metabolism ; Kinetics ; Magnesium/metabolism ; Models, Molecular ; *RNA Splicing ; RNA, Ribosomal/*physiology ; Structure-Activity Relationship ; Tetrahymena
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  • 14
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-02-12
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zeeberg, B R -- Gibson, R E -- Reba, R C -- MH42821-01/MH/NIMH NIH HHS/ -- NS-15080/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Feb 12;239(4841 Pt 1):789-91.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2963379" target="_blank"〉PubMed〈/a〉
    Keywords: Brain/*metabolism ; Haloperidol/therapeutic use ; Humans ; Kinetics ; Receptors, Dopamine/drug effects/*metabolism ; Receptors, Dopamine D2 ; Schizophrenia/*metabolism
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  • 15
    Publication Date: 1988-02-05
    Description: The turnover of phosphatidylinositol 4,5-bisphosphate (PIP2) is believed to constitute a crucial step in the signaling pathways for stimulation of cells by a variety of bioactive substances, including mitogens, but decisive evidence for the idea has not been obtained. In the present study, a monoclonal antibody to PIP2 was microinjected into the cytoplasm of NIH 3T3 cells before or after exposure to mitogens. The antibody completely abolished nuclear labeling with [3H]thymidine induced by platelet-derived growth factor and bombesin, but not by fibroblast growth factor, epidermal growth factor, insulin, or serum. The findings strongly suggest that PIP2 breakdown is crucial in the elicitation and sustaining of cell proliferation induced by some types of mitogens such as platelet-derived growth factor and bombesin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Matuoka, K -- Fukami, K -- Nakanishi, O -- Kawai, S -- Takenawa, T -- New York, N.Y. -- Science. 1988 Feb 5;239(4840):640-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, Tokyo Metropolitan Institute of Gerontology, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2829356" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Antibodies, Monoclonal ; Antigen-Antibody Complex ; Bombesin/*pharmacology ; Cell Division/*drug effects ; Cells, Cultured ; Insulin/pharmacology ; Kinetics ; Mice ; Mice, Inbred Strains ; Phosphatidylinositol 4,5-Diphosphate ; Phosphatidylinositols/immunology/*physiology ; Platelet-Derived Growth Factor/*pharmacology
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  • 16
    Publication Date: 1988-02-26
    Description: Leader peptides that function to direct export of proteins through membranes have some common features but exhibit a remarkable sequence diversity. Thus there is some question whether leader peptides exert their function through conventional stereospecific protein-protein interaction. Here it is shown that the leader peptides retarded the folding of precursor maltose-binding protein and ribose-binding protein from Escherichia coli. This kinetic effect may be crucial in allowing precursors to enter the export pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Park, S -- Liu, G -- Topping, T B -- Cover, W H -- Randall, L L -- GM29798/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Feb 26;239(4843):1033-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Biochemistry/Biophysics Program, Washington State University, Pullman 99164.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3278378" target="_blank"〉PubMed〈/a〉
    Keywords: *ATP-Binding Cassette Transporters ; Bacterial Proteins/*metabolism ; Biological Transport ; Carrier Proteins/metabolism ; Endopeptidase K ; Escherichia coli/*metabolism ; *Escherichia coli Proteins ; Guanidine ; Guanidines/pharmacology ; Kinetics ; Maltose-Binding Proteins ; *Monosaccharide Transport Proteins ; Peptide Hydrolases ; *Periplasmic Binding Proteins ; *Protein Conformation/drug effects ; Protein Denaturation ; Protein Precursors/*metabolism ; Protein Sorting Signals/pharmacology/*physiology ; Serine Endopeptidases/pharmacology ; Spectrometry, Fluorescence
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  • 17
    Publication Date: 1988-10-14
    Description: Suspensions of thymocytes from young rats were incubated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which resulted in a sustained increase in cytosolic free Ca2+ concentration followed by DNA fragmentation and loss of cell viability. Both the Ca2+ increase and DNA fragmentation were prevented in cells treated with the inhibitor of protein synthesis, cycloheximide, and DNA fragmentation and cell killing were not detected when cells were incubated in a "Ca2+-free" medium or pretreated with high concentrations of the calcium probe, quin-2 tetraacetoxymethyl ester. These results indicate that TCDD can kill immature thymocytes by initiating a suicide process similar to that previously described for glucocorticoid hormones.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McConkey, D J -- Hartzell, P -- Duddy, S K -- Hakansson, H -- Orrenius, S -- New York, N.Y. -- Science. 1988 Oct 14;242(4876):256-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Toxicology, Karolinska Institutet, Stockholm, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3262923" target="_blank"〉PubMed〈/a〉
    Keywords: Aminoquinolines ; Animals ; Calcium/metabolism/*pharmacology ; Cell Survival/drug effects ; Cycloheximide/pharmacology ; Cytosol/metabolism ; DNA/metabolism ; Deoxyribonuclease I/*metabolism ; Dioxins/*pharmacology ; Enzyme Activation/drug effects ; Fluorescent Dyes ; Glucocorticoids/pharmacology ; Kinetics ; Rats ; T-Lymphocytes/drug effects ; Tetrachlorodibenzodioxin/*pharmacology ; Thymus Gland/*drug effects/metabolism
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  • 18
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-29
    Description: The kinetics of calcium release by inositol 1,4,5-trisphosphate (IP3) in permeabilized rat basophilic leukemia cells were studied to obtain insight into the molecular mechanism of action of this intracellular messenger of the phosphoinositide cascade. Calcium release from intracellular storage sites was monitored with fura-2, a fluorescent indicator. The dependence of the rate of calcium release on the concentration of added IP3 in the 4 to 40 nM range showed that channel opening requires the binding of at least three molecules of IP3. Channel opening occurred in the absence of added adenosine triphosphate, indicating that IP3 acts directly on the channel or on a protein that gates it. The channels were opened by IP3 in less than 4 seconds. The highly cooperative opening of calcium channels by nanomolar concentrations of IP3 enables cells to detect and amplify very small changes in the concentration of this messenger in response to hormonal, sensory, and growth control stimuli.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer, T -- Holowka, D -- Stryer, L -- AI22449/AI/NIAID NIH HHS/ -- GM24032/GM/NIGMS NIH HHS/ -- GM30387/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 29;240(4852):653-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Sherman Fairchild Center, Stanford University School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2452482" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Basophils ; Benzofurans ; Calcimycin/pharmacology ; Calcium/*metabolism ; Cell Membrane Permeability ; Cytoplasm/metabolism ; Fluorescent Dyes ; Fura-2 ; Inositol 1,4,5-Trisphosphate ; Inositol Phosphates/metabolism/*pharmacology ; Ion Channels/drug effects/*metabolism ; Kinetics ; Leukemia, Experimental/metabolism ; Rats ; Spectrometry, Fluorescence ; Sugar Phosphates/*pharmacology ; Tumor Cells, Cultured
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  • 19
    Publication Date: 1988-10-21
    Description: Studies of the biology and pathogenesis of Kaposi's sarcoma (KS) have been hampered by the inability to maintain long-term cultures of KS cells in vitro. In this study AIDS-KS-derived cells with characteristic spindle-like morphology were cultured with a growth factor (or factors) released by CD4+ T lymphocytes infected with human T-lymphotropic virus type I or II (HTLV-I or HTLV-II) or with human immunodeficiency virus type 1 or 2 (HIV-1 or HIV-2). Medium conditioned by HTLV-II-infected, transformed lines of T cells (HTLV-II CM) contained large amounts of this growth activity and also supported the temporary growth of normal vascular endothelial cells, but not fibroblasts. Interleukin-1 and tumor necrosis factor-alpha stimulated the growth of the KS-derived cells, but the growth was only transient and these could be distinguished from that in HTLV-II CM. Other known endothelial cell growth promoting factors, such as acidic and basic fibroblast growth factors and epidermal growth factor, did not support the long-term growth of the AIDS-KS cells. The factor released by CD4+ T cells infected with human retroviruses should prove useful in studies of the pathogenesis of KS.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nakamura, S -- Salahuddin, S Z -- Biberfeld, P -- Ensoli, B -- Markham, P D -- Wong-Staal, F -- Gallo, R C -- New York, N.Y. -- Science. 1988 Oct 21;242(4877):426-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, MD 20892.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3262925" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/immunology/*pathology ; Antigens, Differentiation, T-Lymphocyte/analysis ; Cell Division ; *Cell Transformation, Viral ; Growth Substances/*isolation & purification/physiology ; Human T-lymphotropic virus 1/*genetics ; Human T-lymphotropic virus 2/*genetics ; Humans ; Kinetics ; Sarcoma, Kaposi/*pathology ; T-Lymphocytes/*immunology ; Tumor Cells, Cultured
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  • 20
    Publication Date: 1988-11-11
    Description: Despite its potential toxicity, H2O2 is used as an extracellular oxidant by Stronglylocentrotus purpuratus eggs to cross-link their fertilization envelopes. These eggs contain 5 mM 1-methyl-N alpha,N alpha-dimethyl-4-mercaptohistidine (ovothiol C), which reacts with H2O2. In consuming H2O2 and being reduced by glutathione, ovothiol acts as a glutathione peroxidase and replaces the function of the enzyme in eggs. The ovothiol system is more effective than egg catalase in destroying H2O2 at concentrations produced during fertilization and constitutes a principal mechanism for preventing oxidative damage at fertilization.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Turner, E -- Hager, L J -- Shapiro, B M -- GM23910/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Nov 11;242(4880):939-41.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3187533" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids, Sulfur/*metabolism ; Animals ; Catalase/metabolism ; Disulfides/metabolism ; Female ; Fertilization ; Glutathione/metabolism ; Glutathione Peroxidase/*metabolism ; Kinetics ; *Methylhistidines ; NADP/metabolism ; Ovum/*metabolism ; Oxidation-Reduction ; Sea Urchins
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  • 21
    Publication Date: 1988-12-16
    Description: Three variations to the structure of the nicotinamide adenine dinucleotide (NAD)-dependent L-lactate dehydrogenase from Bacillus stearothermophilus were made to try to change the substrate specificity from lactate to malate: Asp197----Asn, Thr246----Gly, and Gln102----Arg). Each modification shifts the specificity from lactate to malate, although only the last (Gln102----Arg) provides an effective and highly specific catalyst for the new substrate. This synthetic enzyme has a ratio of catalytic rate (kcat) to Michaelis constant (Km) for oxaloacetate of 4.2 x 10(6)M-1 s-1, equal to that of native lactate dehydrogenase for its natural substrate, pyruvate, and a maximum velocity (250 s-1), which is double that reported for a natural malate dehydrogenase from B. stearothermophilus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wilks, H M -- Hart, K W -- Feeney, R -- Dunn, C R -- Muirhead, H -- Chia, W N -- Barstow, D A -- Atkinson, T -- Clarke, A R -- Holbrook, J J -- New York, N.Y. -- Science. 1988 Dec 16;242(4885):1541-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Bristol, United Kingdom.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3201242" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Geobacillus stearothermophilus/*enzymology/genetics ; Kinetics ; L-Lactate Dehydrogenase/*genetics/metabolism ; Malate Dehydrogenase/*metabolism ; Models, Molecular ; Protein Conformation ; Substrate Specificity
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  • 22
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-10-07
    Description: In vitro autoradiography with 125I-labeled melatonin was used to examine melatonin binding sites in human hypothalamus. Specific 125I-labeled melatonin binding was localized to the suprachiasmatic nuclei, the site of a putative biological clock, and was not apparent in other hypothalamic regions. Specific 125I-labeled melatonin binding was consistently found in the suprachiasmatic nuclei of hypothalami from adults and fetuses. Densitometric analysis of competition experiments with varying concentrations of melatonin showed monophasic competition curves, with comparable half-maximal inhibition values for the suprachiasmatic nuclei of adults (150 picomolar) and fetuses (110 picomolar). Micromolar concentrations of the melatonin agonist 6-chloromelatonin completely inhibited specific 125I-labeled melatonin binding, whereas the same concentrations of serotonin and norepinephrine caused only a partial reduction in specific binding. The results suggest that putative melatonin receptors are located in a human biological clock.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Reppert, S M -- Weaver, D R -- Rivkees, S A -- Stopa, E G -- HD06976/HD/NICHD NIH HHS/ -- HD14427/HD/NICHD NIH HHS/ -- U10-HD22297/HD/NICHD NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1988 Oct 7;242(4875):78-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Developmental Chronobiology, Boston.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2845576" target="_blank"〉PubMed〈/a〉
    Keywords: Autoradiography ; Binding, Competitive ; *Biological Clocks ; Humans ; Hypothalamus/*metabolism ; Iodine Radioisotopes ; Kinetics ; Melatonin/*metabolism ; Optic Chiasm/metabolism ; Receptors, Melatonin ; Receptors, Neurotransmitter/*physiology ; Suprachiasmatic Nucleus/metabolism ; Supraoptic Nucleus/metabolism
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  • 23
    Publication Date: 1988-08-12
    Description: Calcium channels are inactivated by voltage and intracellular calcium. To study the kinetics and the mechanism of calcium-induced inactivation of calcium channels, a "caged" calcium compound, dimethoxy-nitrophen was used to photo-release about 50 microM calcium ion within 0.2 millisecond in dorsal root ganglion neurons. When divalent cations were the charge carriers, intracellular photo-release of calcium inactivated the calcium channel with an invariant rate [time constant (tau) approximately equal to 7 milliseconds]. When the monovalent cation sodium was the charge carrier, photorelease of calcium inside or outside of the cell blocked the channel rapidly (tau approximately equal to 0.4 millisecond), but the block was greater from the external side. Thus the kinetics of calcium-induced calcium channel inactivation depends on the valency of the permeant cation. The data imply that calcium channels exist in either of two conformational states, the calcium- and sodium-permeant forms, or, alternatively, calcium-induced inactivation occurs at a site closely associated with the internal permeating site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Morad, M -- Davies, N W -- Kaplan, J H -- Lux, H D -- R01 HL-16152/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Aug 12;241(4867):842-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Pennsylvania, Department of Physiology, Philadelphia 19104-6085.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2457253" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*physiology/radiation effects ; Cells, Cultured ; Chickens ; Ganglia, Spinal/*physiology/radiation effects ; Ion Channels/*physiology ; Kinetics ; Neurons/*physiology/radiation effects ; Photolysis ; Sodium/metabolism ; *Ultraviolet Rays
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  • 24
    Publication Date: 1988-11-11
    Description: Manganous superoxide dismutase (MnSOD) scavenges potentially toxic superoxide radicals produced in the mitochondria. Tumor necrosis factor-alpha (TNF-alpha) was found to induce the messenger RNA for MnSOD, but not the mRNAs for other antioxidant or mitochondrial enzymes tested. The increase in MnSOD mRNA occurred rapidly and was blocked by actinomycin D, but not by cycloheximide. Induction of MnSOD mRNA was also observed with TNF-beta, interleukin-1 alpha (IL-1 alpha), and IL-1 beta but not with other cytokines or agents tested. TNF-alpha induced MnSOD mRNA in all cell lines and normal cells examined in vitro and in various organs of mice in vivo. These effects of TNF-alpha and IL-1 on target cells may contribute to their reported protective activity against radiation as well as their ability to induce resistance to cell killing induced by the combination of TNF-alpha and cycloheximide.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wong, G H -- Goeddel, D V -- New York, N.Y. -- Science. 1988 Nov 11;242(4880):941-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Genentech, San Francisco, CA 94080.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3263703" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Catalase/metabolism ; Cell Line ; Cycloheximide/pharmacology ; Dactinomycin/pharmacology ; Enzyme Induction/drug effects ; Humans ; Interleukin-1/pharmacology ; Kinetics ; Mice ; Mitochondria/enzymology ; RNA, Messenger/biosynthesis ; Rats ; Superoxide Dismutase/*biosynthesis/genetics/metabolism ; Tissue Distribution ; Tumor Necrosis Factor-alpha/*pharmacology
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  • 25
    Publication Date: 1986-01-31
    Description: p-Chloromercuriphenylsulfonic acid (PCMS), a sulfhydryl inhibitor, prevented the mycelial-to-yeast transition of the dimorphic fungal pathogen, Histoplasma capsulatum. The effect of PCMS was specific for the mycelial-to-yeast transformation; it had no effect on growth of either the yeast or mycelial forms or on the yeast-to-mycelial transition. The failure of PCMS-treated mycelia to transform to yeast was permanent and irreversible. PCMS-treated mycelia could not infect mice but could stimulate resistance to infection by a pathogenic strain of Histoplasma capsulatum. These results suggest a new general strategy for vaccine development in diseases caused by dimorphic pathogens.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Medoff, G -- Sacco, M -- Maresca, B -- Schlessinger, D -- Painter, A -- Kobayashi, G S -- Carratu, L -- AI 07015/AI/NIAID NIH HHS/ -- AI 07172/AI/NIAID NIH HHS/ -- AI 16228/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 31;231(4737):476-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3001938" target="_blank"〉PubMed〈/a〉
    Keywords: 4-Chloromercuribenzenesulfonate/pharmacology ; Animals ; Cytochromes/metabolism ; Energy Metabolism/drug effects ; Fungal Proteins/biosynthesis ; Histoplasma/drug effects/pathogenicity/*physiology ; Histoplasmosis/etiology ; Kinetics ; Mice ; Oxidative Phosphorylation/drug effects ; Oxygen Consumption/drug effects
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  • 26
    Publication Date: 1986-04-04
    Description: Cleavage of phosphatidylinositol 4,5-bisphosphate by phospholipase C results in the production of two important second messengers: inositol-1,4,5-trisphosphate and 1,2-diacylglycerol. Although several receptors promote this cleavage, the molecular details of phospholipase C activation have remained unresolved. In this study, occupancy of a Ca2+-mobilizing receptor, the oligopeptide chemoattractant receptor on human polymorphonuclear leukocyte plasma membranes, was found to lead to the activation of a guanine nucleotide regulatory (N) protein by guanosine 5'-triphosphate. The activated N protein then stimulated a polyphosphoinositide-specific phospholipase C by reducing the Ca2+ requirement for expression of this activity from superphysiological to normal intracellular concentrations. Therefore, the N protein-mediated activation of phospholipase C may be a key step in the pathway of cellular activation by chemoattractants and certain other hormones.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Smith, C D -- Cox, C C -- Snyderman, R -- 5PO1-CA-29589-04/CA/NCI NIH HHS/ -- 5RO1 DEO 3738-12/DE/NIDCR NIH HHS/ -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):97-100.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3006254" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/blood ; Cell Membrane/metabolism ; Enzyme Activation ; GTP-Binding Proteins/*metabolism ; Humans ; Kinetics ; N-Formylmethionine Leucyl-Phenylalanine/pharmacology ; Neutrophils/metabolism ; Phosphatidylinositols/*blood ; Phosphorus Radioisotopes ; Ribonucleotides/blood ; Type C Phospholipases/*blood
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  • 27
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-11-28
    Description: The concentrations of enzyme sites in cells are usually higher than the concentrations of cognate intermediary metabolites. Therefore metabolic pathways or substantial segments of pathways may proceed by the direct transfer of metabolites from one enzyme site to the next by means of enzyme-enzyme complex formation. This mechanism of metabolite transfer differs from that usually assumed where dissociation and random diffusion of metabolite through the aqueous environment is responsible for the transfer to the next enzyme site. Since the direct transfer mechanism does not involve the aqueous environment, the energetics of metabolite interconversion can differ from expectations based on aqueous solution data. Evidence is summarized suggesting that metabolite is transformed and transferred with equal facility everywhere in the direct transfer pathway.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Srivastava, D K -- Bernhard, S A -- GM10451/GM/NIGMS NIH HHS/ -- GM37056/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Nov 28;234(4780):1081-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3775377" target="_blank"〉PubMed〈/a〉
    Keywords: Enzymes/metabolism ; Kinetics ; Metabolism ; Multienzyme Complexes/biosynthesis/*metabolism ; NAD/metabolism
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  • 28
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-12-19
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Strum, D P -- Johnson, B H -- Eger, E I 2nd -- New York, N.Y. -- Science. 1986 Dec 19;234(4783):1586-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3787265" target="_blank"〉PubMed〈/a〉
    Keywords: Adipose Tissue/metabolism ; Animals ; Brain/*metabolism ; Halothane/*metabolism ; Isoflurane/*metabolism ; Kinetics ; Muscles/metabolism ; Rabbits
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  • 29
    Publication Date: 1988-03-04
    Description: Kinetic analysis and protein mutagenesis allow the importance of individual amino acids in ligand binding and catalysis to be assessed. A kinetic analysis has shown that the reaction catalyzed by dihydrofolate reductase is optimized with respect to product flux, which in turn is predetermined by the active-site hydrophobic surface. Protein mutagenesis has revealed that specific hydrophobic residues contribute 2 to 5 kilocalories per mole to ligand binding and catalysis. The extent to which perturbations within this active-site ensemble may affect catalysis is discussed in terms of the constraints imposed by the energy surface for the reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benkovic, S J -- Fierke, C A -- Naylor, A M -- GM24129/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Mar 4;239(4844):1105-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Pennsylvania State University, University Park 16802.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3125607" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Catalysis ; Chemical Phenomena ; Chemistry ; Escherichia coli/enzymology ; Kinetics ; Lactobacillus casei/enzymology ; *Mutation ; Structure-Activity Relationship ; Tetrahydrofolate Dehydrogenase/genetics/*metabolism ; Thermodynamics
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  • 30
    Publication Date: 1988-08-12
    Description: The interaction between receptors and guanine nucleotide binding (G) proteins leads to G protein activation and subsequent regulation of effector enzymes. The molecular basis of receptor-G protein interaction has been examined by using the ability of the G protein from rods (transducin) to cause a conformational change in rhodopsin as an assay. Synthetic peptides corresponding to two regions near the carboxyl terminus of the G protein alpha subunit, Glu311-Val328 and Ile340-Phe350, compete with G protein for interaction with rhodopsin. Amino acid substitution studies show that Cys321 is required for this effect. Ile340-Phe350 and a modified peptide, acetyl-Glu311-Lys329-amide, mimic G protein effects on rhodopsin conformation, showing that these peptides bind to and stabilize the activated conformation of rhodopsin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hamm, H E -- Deretic, D -- Arendt, A -- Hargrave, P A -- Koenig, B -- Hofmann, K P -- EY06062/EY/NEI NIH HHS/ -- EY06225/EY/NEI NIH HHS/ -- RP05369/PHS HHS/ -- etc. -- New York, N.Y. -- Science. 1988 Aug 12;241(4867):832-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Biophysics, University of Illinois College of Medicine, Chicago 60680.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3136547" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antibodies, Monoclonal ; Antigen-Antibody Complex ; Binding Sites ; GTP-Binding Proteins/*metabolism ; Kinetics ; Macromolecular Substances ; Membrane Proteins/*metabolism ; Peptides/metabolism ; Protein Binding ; Protein Conformation ; Retinal Pigments/*metabolism ; Rhodopsin/analogs & derivatives/*metabolism ; Transducin
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  • 31
    Publication Date: 1988-09-02
    Description: Catalysis of amide bond hydrolysis is of singular importance in enzymology. An antibody was induced to an analog of a high-energy intermediate anticipated along the reaction coordinate of amide hydrolysis. This antibody is an amidase with high specificity and a large rate enhancement (250,000) relative to the uncatalyzed reaction. This reaction represents the kinetically most difficult hydrolysis reaction yet catalyzed by an antibody.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Janda, K D -- Schloeder, D -- Benkovic, S J -- Lerner, R A -- New York, N.Y. -- Science. 1988 Sep 2;241(4870):1188-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3413482" target="_blank"〉PubMed〈/a〉
    Keywords: Amidohydrolases/metabolism ; Animals ; Antibodies, Monoclonal/biosynthesis/*physiology ; Antibody Specificity ; Antigens/immunology ; *Catalysis ; Chemical Phenomena ; Chemistry ; Hemocyanin/analogs & derivatives/immunology ; Hydrolysis ; Immunization ; Kinetics ; Mice ; Organophosphorus Compounds/immunology ; Substrate Specificity
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  • 32
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-08-12
    Description: Receptors for N-methyl-D-aspartate (NMDA) are involved in many plastic and pathological processes in the brain. Glycine has been reported to potentiate NMDA responses in neurons and in Xenopus oocytes injected with rat brain messenger RNA. Glycine is now shown to be absolutely required for activation of NMDA receptors in oocytes. In voltage-clamped oocytes, neither perfusion nor rapid pressure application of NMDA onto messenger RNA-injected oocytes caused a distinct ionic current without added glycine. When glycine was added, however, NMDA evoked large inward currents. The concentration of glycine required to produce a half-maximal response was 670 nanomolar, and the glycine dose-response curve extrapolated to zero in the absence of glycine. Several analogs of glycine could substitute for glycine, among which D-serine and D-alanine were the most effective. The observation that D-amino acids are effective will be important in developing drugs targeted at the glycine site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kleckner, N W -- Dingledine, R -- NS17771/NS/NINDS NIH HHS/ -- NS22249/NS/NINDS NIH HHS/ -- NS23804/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Aug 12;241(4867):835-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, University of North Carolina, Chapel Hill 27599-7365.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2841759" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids/pharmacology ; Animals ; Brain/metabolism ; Female ; Glycine/*analogs & derivatives/*pharmacology ; Kinetics ; Oocytes/drug effects/*metabolism ; RNA, Messenger/genetics ; Rats ; Receptors, N-Methyl-D-Aspartate ; Receptors, Neurotransmitter/drug effects/genetics/*metabolism ; Xenopus
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  • 33
    Publication Date: 1988-06-10
    Description: Clinical and seroepidemiological studies in West Africa indicate that human immunodeficiency virus type 2 (HIV-2) is widespread and associated with immunodeficiency states of variable degree. In this study, an isolate of HIV-2 from a patient in Senegal was molecularly cloned and characterized. This isolate (HIV-2ST) was shown by hybridization and restriction enzyme analysis to be more related to the prototype HIV-2ROD than to other human or primate retroviruses. Cultures of HIV-2ST showed genotypic polymorphism, and clones of the virus had transmembrane envelope glycoproteins of 30 and 42 kilodaltons. Unlike other immunodeficiency viruses, HIV-2ST did not cause cell death or induce cell fusion in peripheral blood lymphocytes or in any of four CD4+ cell lines tested. Although HIV-2ST entered cells by a CD4-dependent mechanism and replicated actively, cell-free transmission of the virus was retarded at the level of cell entry. These findings suggest that immunodeficiency viruses prevalent in West African populations are members of the HIV-2 virus group and that certain strains of this virus have attenuated virulence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kong, L I -- Lee, S W -- Kappes, J C -- Parkin, J S -- Decker, D -- Hoxie, J A -- Hahn, B H -- Shaw, G M -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1525-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Internal Medicine, University of Alabama, Birmingham 35294.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3375832" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Line ; Cell Survival ; DNA, Viral/genetics ; Genes, Viral ; HIV/classification/*isolation & purification/pathogenicity ; Humans ; Kinetics ; Lymphocytes/microbiology ; Senegal ; Species Specificity
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  • 34
    Publication Date: 1988-12-16
    Description: Site-directed mutagenesis and expression in Xenopus oocytes were used to study acetylcholine receptors in which serine residues (i) were replaced by alanines (alpha, delta subunits) or (ii) replaced a phenylalanine (beta subunit) at a postulated polar site within the M2 transmembrane helix. As the number of serines decreased, there were decreases in the residence time and consequently the equilibrium binding affinity of QX-222, a quaternary ammonium anesthetic derivative thought to bind within the open channel. Receptors with three serine-to-alanine mutations also displayed a selective decrease in outward single-channel currents. Both the direction of this rectification and the voltage dependence of QX-222 blockade suggest that the residues mutated are within the aqueous pore of the receptor and near its cytoplasmic (inner) surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leonard, R J -- Labarca, C G -- Charnet, P -- Davidson, N -- Lester, H A -- NS-11756/NS/NINDS NIH HHS/ -- NS-8083/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Dec 16;242(4885):1578-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biology, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2462281" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Membrane/*physiology ; Cloning, Molecular ; Electric Conductivity ; Female ; Ion Channels/*physiology ; Kinetics ; Membrane Potentials ; Mutation ; Oocytes/physiology ; RNA, Messenger/genetics ; Receptors, Nicotinic/genetics/*physiology ; Transcription, Genetic ; Xenopus
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  • 35
    Publication Date: 1988-04-01
    Description: A mutant catalytic subunit of adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase has been isolated from Saccharomyces cerevisiae that is no longer subject to regulation yet retains its catalytic activity. Biochemical analysis of the mutant subunit indicates a 100-fold decreased affinity for the regulatory subunit. The mutant catalytic subunit exhibits approximately a threefold increase in Michaelis constant for adenosine triphosphate and peptide cosubstrates, and is essentially unchanged in its catalytic rate. The nucleotide sequence of the mutant gene contains a single nucleotide change resulting in a threonine-to-alanine substitution at amino acid 241. This residue is conserved in other serine-threonine protein kinases. These results identify this threonine as an important contact between catalytic and regulatory subunits but only a minor contact in substrate recognition.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levin, L R -- Kuret, J -- Johnson, K E -- Powers, S -- Cameron, S -- Michaeli, T -- Wigler, M -- Zoller, M J -- GM33986/GM/NIGMS NIH HHS/ -- R35 CA39829-02/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 1;240(4848):68-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cold Spring Harbor Laboratory, NY 11724.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2832943" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Catalysis ; Cyclic AMP/*pharmacology ; Genes, Fungal ; Kinetics ; Macromolecular Substances ; Molecular Sequence Data ; Mutation ; Phosphorylation ; Protein Kinases/*genetics/metabolism ; Saccharomyces cerevisiae/enzymology/*genetics ; Structure-Activity Relationship ; Threonine
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  • 36
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-09-02
    Description: Two groups of mediators, the neuropeptides substance P and K and the monocyte-derived cytokines, interact in the neural regulation of immunological and inflammatory responses. Substance P, substance K, and the carboxyl-terminal peptide SP(4-11) induce the release of interleukin-1, tumor necrosis factor-alpha, and interleukin-6 from human blood monocytes. The neuropeptide effects occur at low doses, are specific as shown by inhibition studies with a substance P antagonist, and require de novo protein synthesis. Since monocyte-derived cytokines regulate multiple cellular functions in inflammation and immunity and since neuropeptides can be released from peripheral nerve endings into surrounding tissues, these findings identify a potent mechanism for nervous system regulation of host defense responses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lotz, M -- Vaughan, J H -- Carson, D A -- AI10386/AI/NIAID NIH HHS/ -- AR21175/AR/NIAMS NIH HHS/ -- AR25443/AR/NIAMS NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1988 Sep 2;241(4870):1218-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Basic and Clinical Research, Research Institute of Scripps Clinic, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2457950" target="_blank"〉PubMed〈/a〉
    Keywords: Cells, Cultured ; Humans ; Interleukin-1/biosynthesis ; Interleukin-6 ; Interleukins/*biosynthesis ; Kinetics ; Monocytes/drug effects/immunology/*metabolism ; Neurokinin A ; Neuropeptides/*pharmacology ; Protein Biosynthesis ; Substance P/pharmacology ; Tumor Necrosis Factor-alpha/*biosynthesis
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  • 37
    Publication Date: 1988-04-15
    Description: Yeast iso-1-cytochrome c (Cc) mutants have been constructed with Phe, Tyr, Gly, Ser, Leu, and Ile at position 82, each with Thr substituted for Cys at position 102. Their long-range electron transfer with zinc-substituted cytochrome c peroxidase (ZnCcP) has been studied by two kinetic techniques. The charge-separated complex, [(ZnCcP)+,FeIICc] converts to [ZnCcP,FeIIICc] by a single, intracomplex electron transfer step that is not governed by "gating" through possible rapid dissociation of the complex or isomerization (for example, heme-ligand) by FeIICc subsequent to its formation from FeIIICc. In every variant with an aliphatic residue at position 82 of Cc, the rate of this electron transfer process is approximately 10(4) slower at approximately 0 degrees C than for the two variants with aromatic residues.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liang, N -- Mauk, A G -- Pielak, G J -- Johnson, J A -- Smith, M -- Hoffman, B M -- GM-33804/GM/NIGMS NIH HHS/ -- HL-13531/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 15;240(4850):311-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Northwestern University, Evanston, IL 60208.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2832950" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acids ; Cytochrome c Group/*metabolism ; Cytochrome-c Peroxidase/*metabolism ; *Cytochromes c ; Electron Transport ; Genetic Variation ; Kinetics ; Peroxidases/*metabolism ; Photolysis ; Saccharomyces cerevisiae/metabolism ; *Saccharomyces cerevisiae Proteins
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  • 38
    Publication Date: 1988-10-07
    Description: In the sarcoplasmic reticulum membrane of skeletal muscle, the ryanodine receptor forms an aqueous pore identified as the calcium-release pathway that operates during excitation-contraction coupling. The purified ryanodine receptor channel has now been shown to have four properties usually associated with gap junction channels: (i) a large nonspecific voltage-dependent conductance consisting of several open states; (ii) an inhibition of open probability by low pH; (iii) an inhibition of open probability by calcium; and (iv) a sensitivity to blockade by heptanol and octanol but not other alcohols. This functional homology may provide an insight into the mechanism of how muscle cells transduce depolarization into an intracellular release of calcium.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ma, J -- Fill, M -- Knudson, C M -- Campbell, K P -- Coronado, R -- GM 36852/GM/NIGMS NIH HHS/ -- HL 37044/HL/NHLBI NIH HHS/ -- HL 39262/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Oct 7;242(4875):99-102.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2459777" target="_blank"〉PubMed〈/a〉
    Keywords: Alcohols/pharmacology ; Animals ; Electric Conductivity ; Intercellular Junctions/*physiology ; Ion Channels/drug effects/*physiology ; Kinetics ; Membrane Potentials ; Muscles/*physiology ; Receptors, Cholinergic/drug effects/isolation & purification/*physiology ; Ryanodine/metabolism/pharmacology ; Ryanodine Receptor Calcium Release Channel ; Sarcoplasmic Reticulum/physiology
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  • 39
    Publication Date: 1988-10-07
    Description: Brief repetitive activation of excitatory synapses in the hippocampus leads to an increase in synaptic strength that lasts for many hours. This long-term potentiation (LTP) of synaptic transmission is the most compelling cellular model in the vertebrate brain for learning and memory. The critical role of postsynaptic calcium in triggering LTP has been directly examined using three types of experiment. First, nitr-5, a photolabile nitrobenzhydrol tetracarboxylate calcium chelator, which releases calcium in response to ultraviolet light, was used. Photolysis of nitr-5 injected into hippocampal CA1 pyramidal cells resulted in a large enhancement of synaptic transmission. Second, in agreement with previous results, buffering intracellular calcium at low concentrations blocked LTP. Third, depolarization of the postsynaptic membrane so that calcium entry is suppressed prevented LTP. Taken together, these results demonstrate that an increase in postsynaptic calcium is necessary to induce LTP and sufficient to potentiate synaptic transmission.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Malenka, R C -- Kauer, J A -- Zucker, R S -- Nicoll, R A -- MH00437/MH/NIMH NIH HHS/ -- MH38256/MH/NIMH NIH HHS/ -- NS24205/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Oct 7;242(4875):81-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pharmacology, School of Medicine, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2845577" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*physiology ; Chelating Agents/pharmacology ; Egtazic Acid/analogs & derivatives/pharmacology ; Evoked Potentials/drug effects ; Hippocampus/*physiology ; In Vitro Techniques ; Kinetics ; Photolysis ; Pyramidal Tracts/physiology ; Rats ; Synapses/*physiology ; *Synaptic Transmission
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  • 40
    Publication Date: 1986-08-15
    Description: The 2.8 A resolution three-dimensional structure of a complex between an antigen (lysozyme) and the Fab fragment from a monoclonal antibody against lysozyme has been determined and refined by x-ray crystallographic techniques. No conformational changes can be observed in the tertiary structure of lysozyme compared with that determined in native crystalline forms. The quaternary structure of Fab is that of an extended conformation. The antibody combining site is a rather flat surface with protuberances and depressions formed by its amino acid side chains. The antigen-antibody interface is tightly packed, with 16 lysozyme and 17 antibody residues making close contacts. The antigen contacting residues belong to two stretches of the lysozyme polypeptide chain: residues 18 to 27 and 116 to 129. All the complementarity-determining regions and two residues outside hypervariable positions of the antibody make contact with the antigen. Most of these contacts (10 residues out of 17) are made by the heavy chain, and in particular by its third complementarity-determining region. Antigen variability and antibody specificity and affinity are discussed on the basis of the determined structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Amit, A G -- Mariuzza, R A -- Phillips, S E -- Poljak, R J -- New York, N.Y. -- Science. 1986 Aug 15;233(4765):747-53.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2426778" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Antibodies, Monoclonal ; *Antigen-Antibody Complex ; Chickens ; Egg White ; Epitopes ; *Immunoglobulin Fab Fragments ; Immunoglobulin Heavy Chains ; Immunoglobulin Light Chains ; In Vitro Techniques ; Kinetics ; Models, Molecular ; Muramidase/*immunology ; Protein Conformation ; X-Ray Diffraction
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  • 41
    Publication Date: 1986-06-20
    Description: In many viral infections the host cell carries the viral genome without producing viral particles, a phenomenon known as viral latency. The cellular mechanisms by which viral latency is maintained or viral replication is induced are not known. The modulation of intracellular calcium concentrations by calcium ionophores induced Epstein-Barr viral antigens in lymphoblastoid cell lines that carry the virus. When calcium ionophores were used in conjunction with direct activators of protein kinase C (12-O-tetradecanoyl phorbol-13-acetate and a synthetic diacylglycerol), a greater induction of viral antigens was observed than with either agent alone. Activation of protein kinase C may be required for the expression of the viral genome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Faggioni, A -- Zompetta, C -- Grimaldi, S -- Barile, G -- Frati, L -- Lazdins, J -- New York, N.Y. -- Science. 1986 Jun 20;232(4757):1554-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3012779" target="_blank"〉PubMed〈/a〉
    Keywords: Aminoquinolines ; Burkitt Lymphoma ; Calcimycin/pharmacology ; Calcium/*pharmacology ; Cell Line ; Cell Transformation, Viral/*drug effects ; Culture Media ; Ethers/pharmacology ; Fluorescent Dyes ; Genes, Viral/*drug effects ; Herpesvirus 4, Human/drug effects/*genetics ; Humans ; Ionomycin ; Kinetics ; Tetradecanoylphorbol Acetate/pharmacology
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  • 42
    Publication Date: 1986-01-31
    Description: High-field carbon-13 nuclear magnetic resonance (NMR) spectroscopy has been used to monitor the isotopic dilution of doubly carbon-13-labeled precursors for 2,3-cyclopyrophosphoglycerate, a novel primary metabolite that occurs in certain methanogens. A unique carbon dioxide fixation pathway that gives rise to asymmetric labeling of acetyl coenzyme A has been demonstrated in Methanobacterium thermoautotrophicum. The effect of selected metabolic inhibitors on the labeled species in the pathway has been examined by NMR. These techniques establish a general, sensitive method for the delineation of convergent biosynthetic pathways.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Evans, J N -- Tolman, C J -- Roberts, M F -- RR 00995/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 31;231(4737):488-91.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3079919" target="_blank"〉PubMed〈/a〉
    Keywords: Acetates/metabolism ; Carbon Dioxide/*metabolism ; Carbon Isotopes ; Euryarchaeota/growth & development/*metabolism ; Kinetics ; Magnetic Resonance Spectroscopy/methods ; Pyruvates/metabolism
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  • 43
    Publication Date: 1986-08-15
    Description: Phosphoglycerate kinase (PGK) is a monomeric protein composed of two domains of approximately equal size, connected by a hinge. Substrate-induced conformational change results in the closure of the active site cleft, which is situated between these two domains. In a study of the relations between structure and function of this enzyme, two interspecies hybrids were constructed, each composed of one domain from the human enzyme and one domain from the yeast enzyme. Despite a 35% difference in the amino acid composition between human and yeast PGK, catalytic properties of the hybrid enzymes are very similar to those of the parental proteins. This result demonstrates that the evolutionary substitutions within these two distantly related molecules do not significantly affect formation of the active site cleft, mechanism of domain closure, or enzyme activity itself.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mas, M T -- Chen, C Y -- Hitzeman, R A -- Riggs, A D -- R01 GM31263/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Aug 15;233(4765):788-90.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3526552" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; *Chimera ; *Genes ; *Genes, Fungal ; Genetic Engineering ; Humans ; Kinetics ; Models, Molecular ; Phosphoglycerate Kinase/*genetics/metabolism ; Plasmids ; Protein Conformation ; Protein Multimerization ; Saccharomyces cerevisiae/enzymology/*genetics
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  • 44
    Publication Date: 1986-04-04
    Description: The human gonadotropin-releasing hormone (GnRH) precursor comprises the GnRH sequence followed by an extension of 59 amino acids. Basic amino acid residues in the carboxyl terminal extension may represent sites of processing to biologically active peptides. A synthetic peptide comprising the first 13 amino acids (H X Asp-Ala-Glu-Asn-Leu-Ile-Asp-Ser-Phe-Gln-Glu-Ile-Val X OH) of the 59-amino acid peptide was found to stimulate the release of gonadotropic hormones from human and baboon anterior pituitary cells in culture. The peptide did not affect thyrotropin or prolactin secretion. A GnRH antagonist did not inhibit gonadotropin stimulation by the peptide, and the peptide did not compete with GnRH for GnRH pituitary receptors, indicating that the action of the peptide is independent of the GnRH receptor. The GnRH precursor contains two distinct peptide sequences capable of stimulating gonadotropin release from human and baboon pituitary cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Millar, R P -- Wormald, P J -- Milton, R C -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):68-70.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3082009" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cells, Cultured ; Follicle Stimulating Hormone/*secretion ; Gonadotropin-Releasing Hormone/*analogs & derivatives/*pharmacology ; Humans ; Kinetics ; Luteinizing Hormone/*secretion ; Papio ; Peptide Fragments/*pharmacology ; Peptides/*pharmacology ; Pituitary Gland, Anterior/drug effects/*secretion ; Protein Precursors/*pharmacology ; Structure-Activity Relationship
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  • 45
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-01-24
    Description: Saccharomyces cerevisiae was examined for tyrosine kinase activity in vitro because this organism offers molecular and genetic approaches for analyzing the role of tyrosine phosphorylation in cellular growth control that are unavailable in higher eukaryotes. Yeast extracts phosphorylated a random copolymer (glutamic acid:tyrosine, 80:20) at tyrosine in a reaction that was linear with respect to time and protein concentration. In the absence of added copolymer, phosphotyrosine was 0.1 percent of the total phosphoamino acids labeled with [gamma-32P]adenosine triphosphate in endogenous yeast proteins. However, specific activities of these reactions were low (approximately 1 percent of those in extracts of chick embryo fibroblasts). Lack of significant incorporation of label from [alpha-32P]adenosine triphosphate into the copolymer or endogenous yeast proteins demonstrated that nucleotide interconversion, adenylylation, and subsequent hydrolysis could not account for the generation of phosphotyrosine observed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schieven, G -- Thorner, J -- Martin, G S -- CA17546/CA/NCI NIH HHS/ -- ES07075/ES/NIEHS NIH HHS/ -- GM21841/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 24;231(4736):390-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2417318" target="_blank"〉PubMed〈/a〉
    Keywords: Kinetics ; Peptides/metabolism ; Phosphorylation ; Phosphotyrosine ; Protein-Tyrosine Kinases/*metabolism ; Saccharomyces cerevisiae/*enzymology/metabolism ; Tyrosine/analogs & derivatives/metabolism
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  • 46
    Publication Date: 1986-04-04
    Description: The human metallothionein-IIA (hMT-IIA) gene contains an enhancer element within its 5' regulatory region. This enhancer element can compete with the SV40 enhancer for one or more cellular factors in vivo. The competition between the two elements is modulated by cadmium, an inducer of hMT-IIA transcription. The data presented are consistent with a model in which heavy metal ions control the ability of the hMT-IIA enhancer to bind a positive factor, leading to increased transcription. The same factor is required for maximal activity of the SV40 enhancer, which suggests that viruses utilize factors that have a normal role in cellular gene expression to control their own genes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scholer, H -- Haslinger, A -- Heguy, A -- Holtgreve, H -- Karin, M -- ES03222/ES/NIEHS NIH HHS/ -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):76-80.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3006253" target="_blank"〉PubMed〈/a〉
    Keywords: Acetyltransferases/genetics ; Animals ; Base Sequence ; Cadmium/pharmacology ; Cell Line ; Cercopithecus aethiops ; Chloramphenicol O-Acetyltransferase ; *Enhancer Elements, Genetic ; *Genes ; *Genes, Regulator ; *Genes, Viral ; Humans ; Kidney ; Kinetics ; Metallothionein/*genetics ; Plasmids ; Simian virus 40/*genetics ; Transcription, Genetic/drug effects ; Transfection
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  • 47
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-12-19
    Description: Monoclonal antibodies elicited to haptens that are analogs of the transition state for hydrolysis of carboxylic esters behaved as enzymic catalysts with the appropriate substrates. These substrates are distinguished by the structural congruence of both hydrolysis products with haptenic fragments. The haptens were potent inhibitors of this esterolytic activity, in agreement with their classification as transition state analogs. Mechanisms are proposed to account for the different chemical behavior of these antibodies with two types of ester substrates. The generation of an artificial enzyme through transition state stabilization by antibodies was thus demonstrated. These studies indicate a potentially general approach to catalyst design.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tramontano, A -- Janda, K D -- Lerner, R A -- GM35318/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Dec 19;234(4783):1566-70.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3787261" target="_blank"〉PubMed〈/a〉
    Keywords: *Antibodies, Monoclonal/immunology ; Binding Sites ; Carboxylic Ester Hydrolases ; *Catalysis ; Chemical Phenomena ; Chemistry ; Esters/immunology/metabolism ; Haptens/immunology ; Hydrolysis ; Kinetics
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  • 48
    Publication Date: 1986-04-25
    Description: A critical enzyme in protein breakdown in Escherichia coli is protease La (the lon gene product), which hydrolyzes proteins and adenosine triphosphate (ATP) in a coupled process. The mechanism of this process was studied with fluorogenic tripeptides. Although proteins and peptides are degraded at the same active site, protein substrates enhance the ability of the enzyme to degrade these peptides two- to tenfold. Proteins that are not substrates had little or no effect. Thus, protein substrates must bind to protease La at two sites, the active site and an allosteric site whose occupancy enhances proteolytic activity. This effect did not require that the proteins themselves be degraded. Proteins could induce peptide breakdown even in the absence of ATP, and proteins and ATP had additive effects in stimulating peptidase activity. A multistep cyclical mechanism is proposed in which the binding of the substrate and ATP activates the protease. The enzyme can then cleave a peptide bond, but is inactivated through ATP hydrolysis. Such a mechanism may help account for the selectivity of protein breakdown and prevent inappropriate or excessive proteolysis in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Waxman, L -- Goldberg, A L -- New York, N.Y. -- Science. 1986 Apr 25;232(4749):500-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2938257" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Dependent Proteases ; Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/*metabolism ; Caseins/pharmacology ; Endopeptidases/*metabolism ; Enzyme Activation/drug effects ; Escherichia coli/enzymology ; *Escherichia coli Proteins ; Glucagon/pharmacology ; *Heat-Shock Proteins ; Intracellular Fluid/enzymology/metabolism ; Kinetics ; *Protease La ; Proteins/metabolism ; *Serine Endopeptidases ; Substrate Specificity
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  • 49
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-01-31
    Description: A shortened form of the self-splicing ribosomal RNA (rRNA) intervening sequence of Tetrahymena thermophila acts as an enzyme in vitro. The enzyme catalyzes the cleavage and rejoining of oligonucleotide substrates in a sequence-dependent manner with Km = 42 microM and kcat = 2 min-1. The reaction mechanism resembles that of rRNA precursor self-splicing. With pentacytidylic acid as the substrate, successive cleavage and rejoining reactions lead to the synthesis of polycytidylic acid. Thus, the RNA molecule can act as an RNA polymerase, differing from the protein enzyme in that it uses an internal rather than an external template. At pH 9, the same RNA enzyme has activity as a sequence-specific ribonuclease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zaug, A J -- Cech, T R -- GM28039/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 31;231(4737):470-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3941911" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Base Sequence ; Binding, Competitive ; *DNA-Directed RNA Polymerases ; Kinetics ; *RNA Splicing ; RNA, Ribosomal/*genetics/metabolism ; Tetrahymena/*genetics
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  • 50
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-10-28
    Description: In cells that do not express immunoglobulin kappa light chain genes, the kappa enhancer binding protein NF-kappa B is found in cytosolic fractions and exhibits DNA binding activity only in the presence of a dissociating agent such as sodium deoxycholate. The dependence on deoxycholate is shown to result from association of NF-kappa B with a 60- to 70-kilodalton inhibitory protein (I kappa B). The fractionated inhibitor can inactivate NF-kappa B from various sources--including the nuclei of phorbol ester-treated cells--in a specific, saturable, and reversible manner. The cytoplasmic localization of the complex of NF-kappa B and I kappa B was supported by enucleation experiments. An active phorbol ester must therefore, presumably by activation of protein kinase C, cause dissociation of a cytoplasmic complex of NF-kappa B and I kappa B by modifying I kappa B. this releases active NF-kappa B which can translocate into the nucleus to activate target enhancers. The data show the existence of a phorbol ester-responsive regulatory protein that acts by controlling the DNA binding activity and subcellular localization of a transcription factor.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Baeuerle, P A -- Baltimore, D -- New York, N.Y. -- Science. 1988 Oct 28;242(4878):540-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research, MA 02142.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3140380" target="_blank"〉PubMed〈/a〉
    Keywords: B-Lymphocytes/physiology ; Cytoplasm/physiology ; DNA-Binding Proteins/physiology ; Enhancer Elements, Genetic ; *Gene Expression Regulation/drug effects ; Humans ; Immunoglobulin kappa-Chains/*genetics ; Kinetics ; Molecular Structure ; Molecular Weight ; Protein Binding ; Regulatory Sequences, Nucleic Acid ; Tetradecanoylphorbol Acetate/pharmacology ; Transcription Factors/*antagonists & inhibitors/physiology
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  • 51
    Publication Date: 1988-05-20
    Description: Immunization with a 41-kilodalton blood stage antigen (p41) of Plasmodium falciparum induces immunity to malaria in monkeys. However, antigenic polymorphism and repetitive amino acids commonly found in protective antigens complicate vaccine development. The gene encoding p41 has now been cloned and analyzed. Sequencing and hybridization studies revealed that the gene structure is highly conserved in 14 parasite isolates from three continents. This finding and the lack of repetitive amino acids in the translated DNA sequence may indicate that p41 has an essential function. In this study the protein was found to be 60 percent homologous to the key glycolytic enzyme aldolase from vertebrates, and the affinity-purified p41 protein from parasites showed aldolase activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Certa, U -- Ghersa, P -- Dobeli, H -- Matile, H -- Kocher, H P -- Shrivastava, I K -- Shaw, A R -- Perrin, L H -- New York, N.Y. -- Science. 1988 May 20;240(4855):1036-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Central Research Units, F. Hoffmann-La Roche and Co., Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3285469" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Antibodies, Protozoan/immunology ; Antigen-Antibody Complex/analysis ; Antigens, Protozoan/genetics/*immunology ; Fructose-Bisphosphate Aldolase/genetics/immunology/*metabolism ; Kinetics ; Plasmodium falciparum/enzymology/*immunology ; Polymorphism, Genetic
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  • 52
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-08-01
    Description: Decanal and N-amino-N'-1-octylguanidine (AOG), combined at 28 microM each, mediated erythrocyte lysis within 80 minutes under physiological conditions. By contrast, no lysis was observed after 20 hours with either decanal (56 microM) or AOG (100 microM) alone. The pronounced synergism observed for these chemicals and similar reactive pairs of chemicals is due to the self-assembly of more cytotoxic hydrazones in situ. Decanal and AOG also exhibit synergistic activity against cultured human cells (HeLa) and bacteria (Escherichia coli J96). This synergism may be useful in the design of cytotoxins that would self-assemble selectively from nontoxic precursors within tumors, while sparing normal tissue.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rideout, D -- 1-F32-CA07723/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1986 Aug 1;233(4763):561-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3523757" target="_blank"〉PubMed〈/a〉
    Keywords: Aldehydes/*metabolism/pharmacology ; Cytotoxins/*metabolism/pharmacology ; Dose-Response Relationship, Drug ; Drug Synergism ; Erythrocytes/drug effects ; Escherichia coli/drug effects ; Guanidines/*metabolism/*pharmacology ; HeLa Cells/drug effects ; Humans ; Kinetics ; Neoplasms/drug therapy
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  • 53
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-12-19
    Description: The immunoglobulin MOPC167, which binds the transition state analog p-nitrophenylphosphorylcholine with high affinity, catalyzed the hydrolysis of the corresponding carbonate 1. MOPC167 catalysis displayed saturation kinetics with catalytic constant (kcat) = 0.4 min-1 and Michaelis constant (Km) = 208 microM, showed substrate specificity, and was inhibited by p-nitrophenylphosphorylcholine. The rate of the reaction was first order in hydroxide ion concentration between pH 6.0 and 8.0. The lower limit for the rate of acceleration of hydrolysis by the antibody above the uncatalyzed reaction was 770. This study begins to define the rules for the generation of catalytic antibodies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pollack, S J -- Jacobs, J W -- Schultz, P G -- New York, N.Y. -- Science. 1986 Dec 19;234(4783):1570-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3787262" target="_blank"〉PubMed〈/a〉
    Keywords: *Antibodies ; Binding Sites ; Carbonates/metabolism ; *Catalysis ; Choline/*analogs & derivatives ; Hydrolysis ; Immunoglobulin A/*metabolism ; Kinetics ; Nitrophenols/metabolism ; Phosphorylcholine/*analogs & derivatives/immunology/metabolism
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  • 54
    Publication Date: 1988-02-26
    Description: Patch clamp recordings of whole-cell and single channel currents revealed the presence of two voltage-sensitive calcium channel types in the membrane of 3T3 fibroblasts. The two calcium channel types were identified by their unitary properties and pharmacological sensitivities. Both calcium channel types were present in all control 3T3 cells, but one type was selectively suppressed in 3T3 cells that had been transformed by activated c-H-ras, EJ-ras, v-fms, or polyoma middle T oncogenes. The presence of voltage-sensitive calcium channels in these nonexcitable cells and the control of their functional expression by transforming oncogenes raises questions about their role in the control of calcium-sensitive processes such as cell motility, cytoskeletal organization, and cell growth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, C F -- Corbley, M J -- Roberts, T M -- Hess, P -- CA21082/CA/NCI NIH HHS/ -- HL37124/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Feb 26;239(4843):1024-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, Harvard Medical School, Boston, MA 02115.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2449730" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/*metabolism ; Calcium Channel Agonists ; Cell Division ; Cell Line ; Cell Line, Transformed ; *Cell Transformation, Neoplastic ; Electric Conductivity ; Fibroblasts/*physiology ; Ion Channels/drug effects/*physiology ; Kinetics ; Membrane Potentials ; Mice ; Nicotinic Acids/pharmacology ; Oncogenes ; *Oxadiazoles
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  • 55
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-10-07
    Description: Adhesion of blood cells to endothelial cells is an essential component of all inflammatory responses. The capacity of the endothelium to support adhesion of neutrophils is increased by cytokines such as tumor necrosis factor-alpha, interleukin-1, and endotoxin. Another cytokine, transforming growth factor-beta (TGF-beta), was a strong inhibitor of basalneutrophil adhesion and also decreased the adhesive response of endothelial cells to tumor necrosis factor-alpha (TNF-alpha). The ability of cells to respond to TGF-beta was related to the duration of culture of endothelial cells after explantation from umbilical veins. TGF-beta is likely to serve an anti-inflammatory role at sites of blood vessel injury undergoing active endothelial regeneration.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gamble, J R -- Vadas, M A -- New York, N.Y. -- Science. 1988 Oct 7;242(4875):97-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Human Immunology, Institute of Medical and Veterinary Science, Adelaide, South Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3175638" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Adhesion/drug effects ; Cells, Cultured ; Endothelium, Vascular/cytology/drug effects/*physiology ; Humans ; Kinetics ; Neutrophils/cytology/drug effects/*physiology ; Transforming Growth Factors/*pharmacology ; Umbilical Veins
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  • 56
    Publication Date: 1988-04-22
    Description: The three-dimensional structure of most enzymes is unknown; however, many enzymes may have structural motifs similar to those in the known structures of functionally related enzymes. Evidence is presented that an enzyme of unknown structure [Ile-transfer RNA (tRNA) synthetase] may share a functionally important structural motif with an enzyme of related function (Tyr-tRNA synthetase). This approach involves (i) identifying segments of Ile-tRNA synthetase that have been unusually conserved during evolution, (ii) predicting the function of one such segment by assuming a structural relation between Ile-tRNA synthetase and Tyr-tRNA synthetase, and (iii) testing the predicted function by mutagenesis and subsequent biochemical analysis. Random mutations were introduced by cassette mutagenesis into a ten-amino-acid segment of Ile-tRNA synthetase that was predicted to be involved in the formation of the binding site for isoleucine. Few amino acid substitutions appear to be tolerated in this region. However, one substitution (independently isolated twice) increased the Michaelis constant Km for isoleucine in the adenylate synthesis reaction by greater than 6000-fold, but had little effect on the Km for adenosine triphosphate, the apparent Km for tRNA, or the rate constant kcat.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Clarke, N D -- Lien, D C -- Schimmel, P -- GM15539/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 22;240(4851):521-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3282306" target="_blank"〉PubMed〈/a〉
    Keywords: *Amino Acyl-tRNA Synthetases ; Binding Sites ; DNA Mutational Analysis ; Escherichia coli/enzymology ; *Isoleucine-tRNA Ligase ; Kinetics ; Protein Conformation ; Saccharomyces cerevisiae/enzymology ; Structure-Activity Relationship
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  • 57
    Publication Date: 1988-03-11
    Description: A complementary DNA encoding the human low density lipoprotein (LDL) receptor under control of the mouse metallothionein-I promoter was injected into fertilized mouse eggs, and a strain of mice expressing high levels of LDL receptors was established. After administration of cadmium, these mice cleared intravenously injected 125I-labeled LDL from blood eight to ten times more rapidly than did normal mice. The plasma concentrations of apoproteins B-100 and E, the two ligands for the LDL receptor, declined by more than 90 percent after cadmium treatment, but the concentration of another apoprotein, A-I, was unaffected. Therefore, overexpression of an endocytotic receptor can dramatically lower the ambient concentration of its ligand in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hofmann, S L -- Russell, D W -- Brown, M S -- Goldstein, J L -- Hammer, R E -- HL 01287/HL/NHLBI NIH HHS/ -- HL 20948/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Mar 11;239(4845):1277-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3344433" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cloning, Molecular ; DNA/genetics ; Female ; *Genes ; Humans ; Kinetics ; Lipoproteins, LDL/*blood ; Mice ; Mice, Transgenic ; Plasmids ; Receptors, LDL/*genetics/metabolism ; Reference Values ; Transcription, Genetic
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  • 58
    Publication Date: 1988-06-10
    Description: The proliferating cell nuclear antigen (PCNA or cyclin) is a nuclear protein recently identified as a cofactor of DNA polymerase delta. When exponentially growing Balb/c3T3 cells are exposed to antisense oligodeoxynucleotides to PCNA, both DNA synthesis and mitosis are completely suppressed. A corresponding sense oligodeoxynucleotide has no inhibitory effects. These experiments indicate that PCNA (cyclin) is important in cellular DNA synthesis and in cell cycle progression.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jaskulski, D -- deRiel, J K -- Mercer, W E -- Calabretta, B -- Baserga, R -- CA 42866/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1544-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, Temple University Medical School, Philadelphia, PA 19140.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2897717" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Autoantigens/*genetics ; Base Sequence ; Cell Division/drug effects ; Cells, Cultured ; Codon ; DNA Replication/*drug effects ; Kinetics ; Mice ; Mice, Inbred BALB C ; Mitosis/*drug effects ; Molecular Sequence Data ; Nuclear Proteins/*genetics ; Oligodeoxyribonucleotides/*pharmacology ; Proliferating Cell Nuclear Antigen
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  • 59
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-07-01
    Description: Synthetic DNA oligomers (tDNAs) corresponding to Escherichia coli tRNA(Phe) or tRNA(Lys) have been synthesized with either deoxythymidine (dT) or deoxyuridine (dU) substituted in the positions occupied by ribouridine or its derivatives. The tDNAs inhibited the aminoacylation of their respective tRNAs with their cognate amino acids, but not the aminoacylation of tRNA(Leu) with Leu. In the presence of aminoacyl-tRNA synthetase, species of both a tDNA(Phe) synthesized with a 3' terminal riboadenosine and a tDNA(Lys) containing only deoxynucleotides could be aminoacylated with the appropriate amino acids, although the Michaelis constant Km and observed maximal rate Vmax values for aminoacylation were increased by three- to fourfold and decreased by two- to threefold, respectively. The aminoacylation of synthetic tDNAs demonstrates that the ribose backbone of a tRNA is not absolutely required for tRNA aminoacylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Khan, A S -- Roe, B A -- GM-30400/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jul 1;241(4861):74-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Oklahoma, Norman 73019.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2455342" target="_blank"〉PubMed〈/a〉
    Keywords: Base Sequence ; DNA/genetics/*metabolism ; Deoxyuridine/metabolism ; Dimethyl Sulfoxide/pharmacology ; Escherichia coli/*genetics ; Hydrogen-Ion Concentration ; Kinetics ; Lysine-tRNA Ligase/metabolism ; Molecular Sequence Data ; Phenylalanine-tRNA Ligase/metabolism ; RNA, Bacterial/*genetics ; RNA, Transfer, Amino Acyl/*genetics ; Spermidine/pharmacology ; Structure-Activity Relationship ; Thymidine/metabolism
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  • 60
    Publication Date: 1986-12-19
    Description: In postmortem studies of patients with schizophrenia, D2 dopamine receptors in the basal ganglia have been observed to be more numerous than in patients with no history of neurological or psychiatric disease. Because most patients with schizophrenia are treated with neuroleptic drugs that block D2 dopamine receptors in the caudate nucleus, it has been suggested that this increase in the number of receptors is a result of adaptation to these drugs rather than a biochemical abnormality intrinsic to schizophrenia. With positron emission tomography (PET), the D2 dopamine receptor density in the caudate nucleus of living human beings was measured in normal volunteers and in two groups of patients with schizophrenia--one group that had never been treated with neuroleptics and another group that had been treated with these drugs. D2 dopamine receptor densities in the caudate nucleus were higher in both groups of patients than in the normal volunteers. Thus, schizophrenia itself is associated with an increase in brain D2 dopamine receptor density.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wong, D F -- Wagner, H N Jr -- Tune, L E -- Dannals, R F -- Pearlson, G D -- Links, J M -- Tamminga, C A -- Broussolle, E P -- Ravert, H T -- Wilson, A A -- Toung, J K -- Malat, J -- Williams, J A -- O'Tuama, L A -- Snyder, S H -- Kuhar, M J -- Gjedde, A -- 1RO1 53146/PHS HHS/ -- NS15080/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1986 Dec 19;234(4783):1558-63.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2878495" target="_blank"〉PubMed〈/a〉
    Keywords: Adult ; Antipsychotic Agents/*therapeutic use ; Caudate Nucleus/*metabolism ; Haloperidol/therapeutic use ; Humans ; Kinetics ; Receptors, Dopamine/*metabolism ; Receptors, Dopamine D2 ; Schizophrenia/drug therapy/*metabolism ; Spiperone/analogs & derivatives/metabolism ; Tomography, Emission-Computed
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  • 61
    Publication Date: 1988-10-14
    Description: Several new synthetic agents show high affinity for binding adenine derivatives. The structures feature complementary hydrogen bonds that cause the molecular chelation of the purine nucleus. The high lipophilicity of the new agents permits the transport of adenosine and deoxyadenosine across organic liquid membranes. The use of synthetic receptors for small biological targets may have application in drug delivery.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benzing, T -- Tjivikua, T -- Wolfe, J -- Rebek, J Jr -- New York, N.Y. -- Science. 1988 Oct 14;242(4876):266-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of Pittsburgh, PA 15260.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3262924" target="_blank"〉PubMed〈/a〉
    Keywords: Adenine/analogs & derivatives/*metabolism ; Biological Transport ; Chloroform ; Deoxyadenosines/metabolism ; *Drug Carriers ; Hydrogen Bonding ; Kinetics ; Membranes, Artificial ; Molecular Structure
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  • 62
    Publication Date: 1988-06-10
    Description: The human platelet-derived growth factor (PDGF) receptor complementary DNA was cloned and expressed by transfection of Chinese hamster ovary (CHO) fibroblasts. The ability of CHO cells expressing the human receptor complementary DNA (CHO-HR5) to interact with different recombinant forms of PDGF (AA and BB homodimers) was tested. Both forms of PDGF bind to the transfected receptor, stimulate the receptor tyrosine kinase activity, and elicit a mitogenic response in a manner that was indistinguishable from the responses of Balb/c 3T3 cells to AA and BB forms of PDGF can be attributed to a single type of receptor and show that the AA form, like the BB form, is a true mitogen.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Escobedo, J A -- Navankasatussas, S -- Cousens, L S -- Coughlin, S R -- Bell, G I -- Williams, L T -- HL-32898/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1532-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, University of California, San Francisco.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2836953" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Division/drug effects ; Cell Line ; Cells, Cultured ; DNA Replication/drug effects ; Enzyme Activation ; Humans ; Kinetics ; Macromolecular Substances ; Mice ; Phosphorylation ; Platelet-Derived Growth Factor/genetics/*metabolism/pharmacology ; Protein-Tyrosine Kinases/*metabolism ; Receptors, Cell Surface/genetics/*metabolism ; Receptors, Platelet-Derived Growth Factor ; Recombinant Proteins/pharmacology ; Transfection
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  • 63
    Publication Date: 1988-06-10
    Description: Previous studies involving platelet-derived growth factor (PDGF) have been based on the premise that a single cell-surface receptor binds all three isoforms of PDGF (AA, BB, and AB). It is now shown that two populations of PDGF receptor exist and can be distinguished by their ligand binding specificity. The B receptor binds only the BB dimer, whereas the A/B receptor binds AA, BB, and AB dimers. Human dermal fibroblasts appear to express seven times as much B receptor as A/B receptor. The B receptor is responsible for most PDGF receptor phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hart, C E -- Forstrom, J W -- Kelly, J D -- Seifert, R A -- Smith, R A -- Ross, R -- Murray, M J -- Bowen-Pope, D F -- DE07063-11/DE/NIDCR NIH HHS/ -- GM35501/GM/NIGMS NIH HHS/ -- HL18645/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 10;240(4858):1529-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Pathology, University of Washington, Seattle 98195.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2836952" target="_blank"〉PubMed〈/a〉
    Keywords: Binding, Competitive ; Cell Membrane/metabolism ; Cells, Cultured ; Fibroblasts/metabolism ; Humans ; Kinetics ; Platelet-Derived Growth Factor/*metabolism ; Receptors, Cell Surface/*metabolism ; Receptors, Platelet-Derived Growth Factor ; Skin/*metabolism ; Structure-Activity Relationship
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  • 64
    Publication Date: 1988-06-17
    Description: Forskolin is commonly used to stimulate adenylate cyclase in the study of modulation of ion channels and other proteins by adenosine 3',5'-monophosphate (cAMP)-dependent second messenger systems. In addition to its action on adenylate cyclase, forskolin directly alters the gating of a single class of voltage-dependent potassium channels from a clonal pheochromocytoma (PC12) cell line. This alteration occurred in isolated cell-free patches independent of soluble cytoplasmic enzymes. The effect of forskolin was distinct from those of other agents that raise intracellular cAMP levels. The 1,9-dideoxy derivative of forskolin, which is unable to activate the cyclase, was also effective in altering the potassium channel activity. This direct action of forskolin can lead to misinterpretation of results in experiments in which forskolin is assumed to selectively activate adenylate cyclase.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hoshi, T -- Garber, S S -- Aldrich, R W -- NS07158/NS/NINDS NIH HHS/ -- NS23294/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 17;240(4859):1652-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neurobiology, Stanford University, School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2454506" target="_blank"〉PubMed〈/a〉
    Keywords: 1-Methyl-3-isobutylxanthine/pharmacology ; Adenylyl Cyclases/*metabolism ; Adrenal Gland Neoplasms/metabolism ; Colforsin/analogs & derivatives/*pharmacology ; Cyclic AMP/metabolism ; Electric Conductivity ; Enzyme Activation/drug effects ; Ion Channels/drug effects/*physiology ; Kinetics ; Pheochromocytoma/metabolism ; Potassium/*metabolism ; Theophylline/pharmacology ; Tumor Cells, Cultured
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  • 65
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-09-23
    Description: The kinetics of microtubule reassembly was studied in vitro by quasi-elastic light scattering (QELS). When microtubules assembled in the absence of microtubule-associated proteins (MAPs) were sheared, they rapidly depolymerized, recovered, and reassembled. The mean length of the recovered microtubules was the same as that observed just before shearing, implying that on average one fragment per original microtubule survived the fragmentation and recovery. When microtubules that contained 25 percent brain MAP were sheared, the fragments did not depolymerize extensively and the average length of the fragments decreased by a factor of 3 relative to the unsheared sample. The results support the dynamic instability model, which predicts that cellular microtubules are latently unstable structures protected on their ends by stabilizing caps.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keates, R A -- Hallett, F R -- New York, N.Y. -- Science. 1988 Sep 23;241(4873):1642-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, University of Guelph, Ontario, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3420415" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Guanosine Diphosphate/physiology ; Guanosine Triphosphate/physiology ; In Vitro Techniques ; Kinetics ; Light ; Microtubule-Associated Proteins/metabolism ; Microtubules/*metabolism ; Scattering, Radiation ; Tubulin/metabolism
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  • 66
    Publication Date: 1988-09-23
    Description: Some strains of human immunodeficiency virus type 1 (HIV-1) can infect primary monocytes and monocyte-derived macrophages in vitro. In this report, the effect of cytokines on the production of one of these strains that shows a tropism for mononuclear phagocytes, designated HIV-1JR-FL, was studied. Primary peripheral blood mononuclear phagocytes infected with HIV-1JR-FL were treated with the hematopoietic factors: granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), macrophage colony-stimulating factor (M-CSF), and gamma-interferon (gamma-IFN). The M-CSF, GM-CSF, IL-3, and gamma-IFN were able to alter HIV-1 production under different conditions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Koyanagi, Y -- O'Brien, W A -- Zhao, J Q -- Golde, D W -- Gasson, J C -- Chen, I S -- New York, N.Y. -- Science. 1988 Sep 23;241(4873):1673-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Immunology, UCLA School of Medicine 90024.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3047875" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Products/*pharmacology ; Colony-Stimulating Factors/pharmacology ; Cytokines ; Granulocyte-Macrophage Colony-Stimulating Factor ; Growth Substances/pharmacology ; HIV/*physiology ; Humans ; Interleukin-3/pharmacology ; Kinetics ; Macrophages ; Monocytes/*microbiology ; *Virus Replication
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  • 67
    Publication Date: 1986-04-04
    Description: The pathophysiology of anaphylaxis is very complex, and the sequelae of events are not fully explained in terms of the effects of histamine and peptide leukotrienes alone. Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, PAF-acether) has been detected in animals undergoing anaphylaxis. Injection of synthetic PAF-acether induces similar effects, including bronchoconstriction, respiratory arrest, systemic hypotension, neutropenia, and thrombocytopenia. The results reported here demonstrate that the histamine- and leukotriene-independent component of guinea pig anaphylaxis in vivo and in isolated lung parenchymal strips in vitro is mediated by PAF-acether. However, PAF-acether is not responsible for the anaphylaxis-induced thrombocytopenia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Darius, H -- Lefer, D J -- Smith, J B -- Lefer, A M -- HL-25575/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):58-60.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3082008" target="_blank"〉PubMed〈/a〉
    Keywords: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine ; Alprazolam ; *Anaphylaxis ; Animals ; Anti-Inflammatory Agents/pharmacology ; Benzodiazepines/pharmacology ; Blood Pressure ; Diphenhydramine/pharmacology ; Guinea Pigs ; In Vitro Techniques ; Kinetics ; Lung/drug effects/*immunology ; Male ; Ovalbumin ; Platelet Activating Factor/*immunology ; Platelet Count/drug effects ; Pyrazoles/pharmacology
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  • 68
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-01-31
    Description: Pineal melatonin may play an important role in regulation of vertebrate circadian rhythms and in human affective disorders. In some mammals, such as hamsters and sheep, melatonin is involved in photoperiodic time measurement and in control of reproduction. Although wild mice (Mus domesticus) and some wild-derived inbred strains of mice have melatonin in their pineal glands, several inbred strains of laboratory mice (for example, C57BL/6J) were found not to have detectable melatonin in their pineal glands. Genetic analysis suggests that melatonin deficiency in C57BL/6J mice results from mutations in two independently segregating, autosomal recessive genes. Synthesis of melatonin from serotonin in the pineal gland requires the enzymes N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). Pineal glands from C57BL/6J mice have neither NAT nor HIOMT activity. These results suggest that the two genes involved in melatonin deficiency are responsible for the absence of normal NAT and HIOMT enzyme activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ebihara, S -- Marks, T -- Hudson, D J -- Menaker, M -- 13162/PHS HHS/ -- FO5TW03377/TW/FIC NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 31;231(4737):491-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3941912" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Chromatography, High Pressure Liquid ; Female ; Kinetics ; Male ; Melatonin/biosynthesis/deficiency/*genetics ; Mice ; Mice, Inbred C57BL ; Mice, Inbred Strains ; Pineal Gland/*metabolism ; Reference Values ; Species Specificity
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  • 69
    Publication Date: 1986-01-10
    Description: The catalytically essential amino acid in the active site of bacterial alkaline phosphatase (Ser-102) has been replaced with a cysteine by site-directed mutagenesis. The resulting thiol enzyme catalyzes the hydrolysis of a variety of phosphate monoesters. The rate-determining step of hydrolysis, however, is no longer the same for catalysis when the active protein nucleophile is changed from the hydroxyl of serine to the thiol of cysteine. Unlike the steady-state kinetics of native alkaline phosphatase, those of the mutant show sensitivity to the leaving group of the phosphate ester.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ghosh, S S -- Bock, S C -- Rokita, S E -- Kaiser, E T -- AM 07122-02/AM/NIADDK NIH HHS/ -- New York, N.Y. -- Science. 1986 Jan 10;231(4734):145-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3510454" target="_blank"〉PubMed〈/a〉
    Keywords: *2,4-Dinitrophenol/*analogs & derivatives ; Alkaline Phosphatase/*genetics/metabolism ; Amino Acid Sequence ; Binding Sites ; DNA/genetics ; Dinitrophenols/metabolism ; Escherichia coli/enzymology/genetics ; Kinetics ; Mutation ; Nitrophenols/metabolism ; Organophosphates/metabolism ; Organophosphorus Compounds/metabolism ; Plasmids
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  • 70
    Publication Date: 1986-04-04
    Description: Platelet-derived growth factor (PDGF) is a potent mitogen for vascular smooth muscle cells that has been implicated in the pathogenesis of atherosclerosis. The potential role of PDGF in the altered vasoreactivity of atherosclerotic vessels has been studied through an examination of its effects on contractility in the rat aorta. PDGF caused a concentration-dependent contraction of aortic strips and was significantly more potent on a molar basis than the classic vasoconstrictor peptide angiotensin II. Furthermore, PDGF increased the cytosolic free calcium concentration in cultured rat aortic smooth muscle cells. These observations suggest a new biological activity for PDGF that may contribute to the enhanced vasoreactivity of certain atherosclerotic vessels.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Berk, B C -- Alexander, R W -- Brock, T A -- Gimbrone, M A Jr -- Webb, R C -- HL20054/HL/NHLBI NIH HHS/ -- HL22602/HL/NHLBI NIH HHS/ -- HL35013/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):87-90.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3485309" target="_blank"〉PubMed〈/a〉
    Keywords: Aminoquinolines ; Angiotensin II/pharmacology ; Animals ; Aorta/*drug effects/metabolism/physiology ; Calcium/metabolism ; Cytosol/metabolism ; Dose-Response Relationship, Drug ; Epidermal Growth Factor/pharmacology ; Fluorescent Dyes ; Homeostasis/drug effects ; Humans ; In Vitro Techniques ; Kinetics ; Platelet-Derived Growth Factor/*pharmacology ; Rats ; Vasoconstriction/*drug effects
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  • 71
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-04-04
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brown, M S -- Goldstein, J L -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):34-47.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3513311" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Transport ; Cholesterol/*metabolism ; Endocytosis ; *Homeostasis ; Humans ; Hyperlipoproteinemia Type II/*metabolism ; Kinetics ; Lipid Metabolism, Inborn Errors/metabolism ; Lipoproteins, HDL/blood ; Lipoproteins, LDL/blood/*metabolism ; Models, Biological ; Mutation ; Receptors, LDL/genetics/*metabolism
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  • 72
    Publication Date: 1986-11-14
    Description: The term "nuclear rotation" refers to a motion of nucleoli within interphase nuclei of several cell types. No mechanism or function has been ascribed to this phenomenon, and it was unknown whether nuclear structures in addition to nucleoli participate in this motion. Moreover, it was unclear whether nuclear rotation occurs independent of concurrent motion of juxtanuclear cytoplasm. The work reported here presents quantitative evidence, for three-dimensional intranuclear, tandem motion of fluorescently labeled chromatin domains associated with nucleoli and those remote from nucleoli. The results show that such motion is curvilinear, that it is not restricted to nucleoli, and, moreover, that it occurs independently of motion of juxtanuclear, cytoplasmic structures. These results suggest that this motion represents karyoplasmic streaming and its function is to transpose to nuclear pores those chromatin domains actively transcribed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉De Boni, U -- Mintz, A H -- New York, N.Y. -- Science. 1986 Nov 14;234(4778):863-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3775367" target="_blank"〉PubMed〈/a〉
    Keywords: Cell Nucleolus/*physiology/ultrastructure ; *Chromatin ; Fluorescent Dyes ; Histocytochemistry ; Indoles ; *Interphase ; Kinetics ; Movement ; Neurons/*ultrastructure ; Nuclear Envelope/physiology
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  • 73
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-08-29
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hait, W N -- Harding, M W -- Handschumacher, R E -- New York, N.Y. -- Science. 1986 Aug 29;233(4767):987-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3016900" target="_blank"〉PubMed〈/a〉
    Keywords: 3',5'-Cyclic-AMP Phosphodiesterases/metabolism ; Animals ; Calmodulin/*metabolism ; Carrier Proteins/*metabolism ; Cattle ; Cyclosporins/*metabolism/pharmacology ; Humans ; Kinetics ; Peptidylprolyl Isomerase ; Rabbits
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  • 74
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1986-04-04
    Description: Contraction and myosin light-chain phosphorylation were measured in electrically stimulated tracheal smooth muscle. Latencies for the onset of force, stiffness, and light-chain phosphorylation were 500 milliseconds. Myosin light chain was phosphorylated from 0.04 to 0.80 mole of phosphate per mole of light chain with a pseudo-first-order rate of 1.1 per second with no evidence of an ordered or negatively cooperative process. Following the period of latency, stiffness increased with phosphorylation and both increased more rapidly than isometric force. The linear relation between stiffness and phosphorylation during activation suggests independent attachment of each myosin head upon phosphorylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kamm, K E -- Stull, J T -- HL 26043/HL/NHLBI NIH HHS/ -- HL 32607/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1986 Apr 4;232(4746):80-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3754063" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Carbachol/pharmacology ; Electric Stimulation ; In Vitro Techniques ; Kinetics ; *Muscle Contraction/drug effects ; Muscle, Smooth/*physiology ; Myosin-Light-Chain Kinase ; Myosins/*metabolism ; Phosphorylation ; Protein Kinases/metabolism ; Trachea/physiology
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  • 75
    Publication Date: 1986-03-07
    Description: The crystal structures and enzymic properties of two mutant dihydrofolate reductases (Escherichia coli) were studied in order to clarify the functional role of an invariant carboxylic acid (aspartic acid at position 27) at the substrate binding site. One mutation, constructed by oligonucleotide-directed mutagenesis, replaces Asp27 with asparagine; the other is a primary-site revertant to Ser27. The only structural perturbations involve two internally bound water molecules. Both mutants have low but readily measurable activity, which increases rapidly with decreasing pH. The mutant enzymes were also characterized with respect to relative folate: dihydrofolate activities and kinetic deuterium isotope effects. It is concluded that Asp27 participates in protonation of the substrate but not in electrostatic stabilization of a positively charged, protonated transition state.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Howell, E E -- Villafranca, J E -- Warren, M S -- Oatley, S J -- Kraut, J -- F32 GM09375/GM/NIGMS NIH HHS/ -- GM10928/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1986 Mar 7;231(4742):1123-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3511529" target="_blank"〉PubMed〈/a〉
    Keywords: *Aspartic Acid ; Crystallography ; Deuterium ; Escherichia coli ; Kinetics ; Methotrexate/metabolism ; Mutation ; Protein Binding ; Structure-Activity Relationship ; *Tetrahydrofolate Dehydrogenase
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