ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A two-dimensional NMR study of exchange behavior of amide hydrogens in a lysozyme derivative with an extra cross-link between Glu35 and Trp 108 - quenching of cooperative fluctuations and effects on the protein stability (1997)
    New York : Wiley-Blackwell
    Biopolymers 41 (1997), S. 131-143 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two dimensional nmr spectra [correlated spectroscopy (COSY), homonuclear Hartmann-Hahn (HOHAHA), nuclear Overhauser effect spectroscopy (NOESY)] have been observed for cross-linked lysozyme, a chemically modified lysozyme derivative with an extra ester cross-link between residues E35 and W108. Eight shifted cross-peaks were found in the fingerprint region of COSY spectra. By searching COSY, HOHAHA and NOESY spectra, they have been assigned to A32, E35, S36, I58, A107, W108, V109, and A110. The NOE connectivities (dNN and dαN) found for the cross-linked lysozyme are quite similar to those for the intact lysozyme.Exchange behavior of amide hydrogens has been studied for both intact and cross-linked lysozymes by observing the fingerprint region of COSY spectra. Hydrogen exchange reactions were carried out at pH 7.0 and at several temperatures. There exist 41 amide hydrogens whose exchange reactions are detectable under this experimetal conditon. Not only exchange rates but also their activation enthalpies were determined for individual amide hydrogens. They are classified into two groups, which are called categories III and IV. Category III hydrogens are distributed in relatively flexible peripheral parts of protein, and category IV hydrogens are deeply buried in the core region of protein. Category III hydrogens are exchanged through localized unfolding around their sites with a low activation enthalpy ranging from 10 to 25 kcal/mol. The formation of an extra cross-link affects neither the exchange rate nor the activation enthalpy of category III hydrogens. However, amide hydrogens of residues 34-39 in the vicinity of the hinge are exceptions. They are easily exchanged in the intact lysozyme but their exchange rates are drastically retarded by cross-linking. In the intact lysozyme, structural fluctuations mediating the exchange of category IV hydrogens are highly cooperative with a large activation enthalpy. These large-scale structural fluctuations are the global unfolding of the overall structure and also concerted motions within a domain. Especially near 38°C, it was found that the dominant fluctuation occurring in the α-domain is different from that in the β-domain. However, these concerted motions are strongly quenched by the formation of the cross-link because of the cooperativity of such a large-scale fluctuation. The stabilization of a localized area of protein by cross-linking results in the great suppression of large-scale and concerted motions. The exchange rates of category IV hydrogens are extremely retarded in the cross-linked lysozyme, so that they are exchanged through the so-called penetration mechanism characterized by a low activation enthalpy. These expeimental results are discussed with regard to the contribution of cross-linking to the stabilization of the folded structure of protein. © 1997 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Pheromone Synthesis, CLXXVIPart CLXXV: H. Takikawa, M. Takenaka, K. Mori, Liebigs Ann., in press.. Synthesis of the Four Stereoisomers of 3,13-Dimethylheptadecane, the Major Sex Pheromone Component of the Western False Hemlock Looper (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1965-1970 
    Details
    ISSN: 0947-3440
    Keywords: Grignard coupling ; Heptadecane, 3,13-dimethyl- ; Nepytia freemani ; Phenylsulfone, alkylation of ; Pheromone, optically active ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: All of the four stereoisomers of 3,13-dimethylheptadecane (1), the female-produced sex pheromone of the western false hemlock looper (Nepytia freemani), were synthesized by starting from the enatiomers of citronellol (2a) and 2-methyl-1-butanol (4a).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    4,4′,4″-Tris(stearoylamino)triphenylamine as a novel material for functional molecular gels (1996)
    Weinheim : Wiley-Blackwell
    Advanced Materials 8 (1996), S. 740-741 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19960080907
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Enhancement of antibody production by growth factor addition in perfusion and hollow-fiber culture systems (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 673-680 
    Details
    ISSN: 0006-3592
    Keywords: bovine serum albumin ; growth factor ; hollow-fiber culture ; perfusion culture ; antibody production rate ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of the high-molecular-weight growth factors, transferrin and bovine serum albumin (BSA), on antibody production were analyzed quantitatively in continuous hollow-fiber cultivation over a period of 60 days. Transferrin enhanced cell growth but had no significant effect on the specific antibody production rate, whereas BSA significantly enhanced antibody production. The antibody production rate was increased 4- and 14-fold respectively by feeding BSA at 2 and 5 g L-1 into the EC side of the system (the side connected to the cell-containing outer part of the hollow-fiber unit) compared with the production achieved without BSA. Addition of 5 g L1 BSA into the IC side of the system (the side connected to the inner part of the hollow-fiber unit) resulted in a 2.5-fold increase in the antibody production rate. The effect of BSA was also analyzed using the perfusion culture system with a separation unit. When fresh medium containing either 2 or 5 g L-1 BSA was fed into the reactor, both the specific growth rate and specific death rate increased, while the specific antibody production rate was increased 2- and 25-fold, respectively, by feeding BSA at these two concentrations compared with no addition. Comparing the two systems, the increase in the antibody production rate achieved with the hollow-fiber system was threefold greater than that in the perfusion culture system with the same concentration of BSA feeding. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480616
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Trapping of Radicals in the Coordination Spheres of Metals (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1005-1008 
    Details
    ISSN: 0947-6539
    Keywords: alkali metals ; calcium ; ketyl radicals ; radicals ; samarium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of hexamethylphosphoramide (HMPA) or other sterically demanding groups as stabilizing ligands allows the successful isolation of a series of structurally characterizable complexes of ketyl radicals with alkali, alkaline earth, and lanthanide metal. It has been demonstrated that the stability and reactivity of the ketyl radicals strongly depend on both the nature of the metals to which they are bound and the steric and electronic properties of the ancillary ligands, as well as the structure of their parent ketones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030704
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of poly(1-benzoylsemicarbazide) and poly(1,3,4-oxadiazole amine) from 2-(p-aminophenyl)-1,3,4-oxadizolin-5-one via ring-opening (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 667-673 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A novel thermally stable and semiconducting polyheterocycle, poly(1,3,4-oxadiazole amine), was synthesized from 2-(p-aminophenyl)-1,3,4-oxadiazolin-5-one via ring-opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4-oxadiazole heterocyclic units. The polymer is highly thermally stable and exhibits no weight loss up to 370°C in air. Its electric conductivity is less than 10-10 S · cm-1 at ambient temperature, but markedly increases to 6,5 · 10-7 S · cm-1 upon doping with iodine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030171001
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of 1,3,4-oxadiazole-containing polyethers from 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole and various aromatic diols (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 1799-1808 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Six 1,3,4-oxadiazole-containing polyethers with reduced viscosities of 0,65-1,17 dL · g-1 were synthesized by high-temperature solution polycondensation of an activated difluoride, 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole, with aromatic diols possessing a variety of ring structures. The expected chemical structures were confirmed by IR and 1H NMR spectroscopy and elemental analysis. Of all the polymers, two polyethers were highly crystalline and soluble only in limited solvents such as o-chlorophenol and conc. sulfuric acid. The other polyethers were amorphous and dissolved readily in a variety of organic media including polar aprotic solvents, phenols and chlorinated hydrocarbons. Colorless to slightly yellow-colored, transparent and tough films could be cast from the N-methyl-2-pyrrolidone or o-chlorophenol solutions. The mechanical properties were excellent and their tensile strength, elongation at break and tensile moduli were in the ranges of 53-80 MPa, 4-12% and 1,3-2,0 GPa, respectively. The amorphous polyethers had high glass transition temperatures of 195-259°C. All the polyethers were highly thermally and thermooxidatively stable and exhibited no weight loss up to 400°C, with 10% weight loss being recorded at 464-514°C in air.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980609
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Arsenobetaine as the major arsenic compound in the muscle of two species of freshwater fish (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 9 (1995), S. 105-109 
    Details
    ISSN: 0268-2605
    Keywords: arsenic ; arsenobetaine ; freshwater fish ; rainbow trout ; Japanese smelt ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical form of arsenic contained in the muscle of certain freshwater fish was examined using cultured specimens of rainbow trout (Salmo gairdneri) and wild specimens of Japanese smelt (Hypomesus nipponensis). More than 95% of the total arsenic of both species was extracted with methanol and recovered in the water-soluble fraction. The major arsenic compound of both species was purified by cation-exchange chromatography on Dowex 50, gel filtration on Bio-Gel P-2 and HPLC on Asahipak GS-220H. Behavior in the above purification procedure and analyses of the purified compounds by HPLC-ICP and TLC confirmed that the major arsenic compound of both species was arsenobetaine. Arsenobetaine found in cultured rainbow trout seems to be derived from the commercial assorted feed containing arsenobetaine as the major arsenical. On the other hand, the result with wild Japanese smelt suggested that arsenobetaine is a naturally occurring compound in the freshwater environment.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590090203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Sodium alkyl ether sulfate preparative electrophoresis for the preparation of reaction centers without H-subunit from Rhodopseudomonas viridis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 319-322 
    Details
    ISSN: 0173-0835
    Keywords: Sodium alkyl ether sulfate ; Membrane protein ; Photosynthetic reaction center ; Subunit deletion ; Preparative electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Sodium alkyl ether sulfate (AES), an analog of sodium dodecyl sulfate (SDS) was used in polyacrylamide gel electrophoresis (PAGE) for the partial decomposition of the photosynthetic reaction center (RC) of Rhodopseudomonas viridis. Unlike SDS, AES did not completely dissociate RC into its subunits but selectively detached H-subunit from RC to give RC(-H) without losing the spectroscopic nature of RC. For the denaturation of RC(-H), AES was found to be as mild as 3-[3-cholamidopropyl dimethylammonio]-1-propanesulfonate (CHAPS).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190229
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Fractal-like behavior of a mass-transport process (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 2187-2193 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: After an aqueous solution containing Sr2+ was flowed through a bed packed with particles of activated charcoal for a very long time, the flow was abruptly switched to deionized water. The variation in ionic concentration at the outlet with time was characterized by the power law, Cout ∼ t-α, for sufficiently large t. This fractal-like behavior we reported previously has further been studied theoretically and experimentally. A major concern is to examine dependency of α on experimental conditions. Adsorption sites predominate over dead-end pores or spaces as “trappers” in our case where Sr2+ or Ba2+ is adsorbed on activated charcoal. The experimental results can well be explained by our theoretical model. It has been found, however, that the response curve for Sr2+ deviates from the power law after a very long time. This deviation can be explained by introducing the assumption that there exists a maximum value of the activation energy for the desorption process. The curve for Ba2+, on the other hand, exhibits no such deviation until Cout decreases to the detection limit of the analytical device used.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690430905
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...