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  • semisynthesis  (3)
  • Gangliosides  (1)
  • Inorganic Chemistry  (1)
  • 1
    ISSN: 1573-4943
    Schlagwort(e): aprotinin ; bovine pancreatic trypsin inhibitor ; semisynthesis ; inhibitory specificity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The semisynthesis of homologues of aprotinin, the bovine pancreatic trypsin inhibitor, is described. The P1 lysine15 residue was replaced by two methods. The first procedure, which consisted of two enzymatic steps for the incorporation of other amino acids has previously been described. The second approach consisted of six steps of both enzymatic and chemical nature. The modified inhibitor, in which the lysine15-alanine16 peptide bond is hydrolyzed, was used as the starting material. All carboxyl groups of the modified inhibitor were esterified with methanol; the lysine15 methylester group was then selectively hydrolyzed. Afterward, lysine15 itself was split off. Arginine, glutamic acid, methionine, andl-2-aminohexanoic acid (norleucine, Nle) were incorporated using water-soluble carbodiimide combined with an acylation catalyst. The methylester group was used to prevent polymerization. The reactive-site peptide bonds were resynthesized using either chymotrypsin or trypsin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    The protein journal 10 (1991), S. 245-251 
    ISSN: 1573-4943
    Schlagwort(e): Aprotinin ; bovine pancreatic trypsin inhibitor ; enzymatic synthesis ; semisynthesis ; inhibitory specificity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The replacement of amino acids in the P′1 and P′2 position of aprotinin, the bovine pancreatic trypsin inhibitor, is described. Using the “modified” inhibitor as starting material, with the hydrolyzed reactive-site peptide bond Lys15-Ala16, the residues P′1 (Ala16) and P′2 (Arg17) were split off by the action of aminopeptidase K. Incorporation of suitable dipeptides containing a basic residue (Lys or Arg) in the C-terminal position was carried out in a “one pot” reaction involving trypsin-catalyzed coupling. In this way, the native fragment Ala16-Arg17 was reintroduced and also replaced by Gly-Arg, Ala-Lys, and Leu-Arg yielding intact inhibitor molecules. The mechanism for incorporation of dipeptides was investigated by treating the aprotinin derivative with the Arg17-Ile18 peptide bond hydrolyzed with trypsin under proteosynthetic conditions. We established that only inhibitor molecules cleaved between Lys15 and Xaa16 are intermediates leading to the desired products. The inhibitory properties of the new aprotinin homologues were tested, and the significance of the P′1 residue for the inhibition of trypsin, kallikrein, and chymotrypsin was deduced.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    The protein journal 10 (1991), S. 527-533 
    ISSN: 1573-4943
    Schlagwort(e): Aprotinin ; bovine pancreatic trypsin inhibitor ; semisynthesis ; inhibitory specificity ; kallikrein inhibition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract An extended concept for the replacement of amino acids in theP' region of aprotinin by chemical semisynthesis is presented. Either fragment condensation with dipeptides protected as tert-butyl ester or stepwise introduction of two single amino acid-tert-butyl esters into a partially esterified aprotinin derivative (with free Lys15-carboxyl group) lacking the amino acids Ala16 and Arg17 leads to aprotinin homologues and derivatives mutated in theP′ 1 andP′ 2 position. This method may complement the recently reported enzymatic synthesis by enabling access to aprotinin homologues and derivatives, which cannot be prepared enzymatically. The synthesis of [Ala17]BPTI and [seco-17/18]BPTI is described in detail.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1573-4986
    Schlagwort(e): Gangliosides ; human granulocytes ; TLC overlay assay ; receptor ; influenza A virus ; Sendai virus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The structures of gangliosides from human granulocytes were elucidated by fast atom bombardment mass spectrometry and by gas chromatography/mass spectrometry as their partially methylated alditol acetates. In human granulocytes besides GM3 (II3Neu5Ac-LacCer), neolacto-series gangliosides (IV3Neu5Ac-nLcOse4Cer, IV6Neu5Ac-nLcOse4Cer and VI3Neu5Ac-nLcOse6Cer) containing C24:1, and to some extent C22:0; and C16:0 fatty acid in their respective ceramide portions, were identified as major components. In this study we demonstrate that gangliosides from human granulocytes, the second most abundant cells in peripheral blood, can serve as receptors for influenza viruses A/PR/8/34 (H1N1), A/X-31 (H3N2), and a parainfluenza virus Sendai virus (HNF1, Z-strain). Viruses were found to exhibit specific adhesion to terminal Neu5Acα2-3Gal and/or Neu5Acα2-6Gal sequences as well as depending on the chain length of ganglioside carbohydrate backbones from human granulocytes, these important effector cells which represent the first line of defence in immunologically mediated reactions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 3318-3323 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Diphenylmethylen entstand bei der Photolyse von Triphenylphosphin-diphenylmethylen (1) und bei dem spontanen Zerfall des Trimethylammonium-diphenylmethylids (10). Es zeigte nur radikalisches Verhalten und stabilisierte sich durch Entzug von Wasserstoffatomen aus dem Lösungsmittel (bzw. dem Cyclohexen) unter Bildung von Diphenylmethan bzw. Tetraphenyläthan.  -  Mit etwa gleicher Geschwindigkeit, mit der der Zerfall des Benzhydrylids 10 erfolgte, verlief die Stevenssche Umlagerung zu [α.α-Diphenyl-äthyl]-dimethylamin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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