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  • Biochemistry  (1)
  • RP-HPLC analysis  (1)
  • active region  (1)
  • 1
    ISSN: 1573-3904
    Schlagwort(e): Biological activity ; Isomer ratio ; RP-HPLC analysis ; Topological isomer ; Two-step disulfide bond formation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In a two-step selective disulfide-bond-forming reaction of human uroguanylin, a 16-residue peptide with two intramolecular disulfide bonds, two compounds (I and II) were formed, which could be detected by RP-HPLC after the second disulfide-bond-forming reaction and were isolated as single entities. Their primary structures, molecular weights, and disulfide connectivities proved to be identical, but their optical rotation values were different, suggesting that they are topological isomers. Only compound I was found to increase the cGMP levels in cultured T84 cells significantly. The ratio of these compounds was affected by the order of the disulfide-bond-forming reactions, but not by the solvent used. The presence of a carboxyl-terminal leucine residue seems to be crucial for stabilizing the conformation of the two isomers.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1075-2617
    Schlagwort(e): Solution synthesis ; human midkine ; powerful solvent system ; powerful solvent system ; active region ; Chemistry ; Biochemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Human midkine (hMK), a novel heparin-binding neurotrophic factor consisting of 121 amino acid residues with five intramolecular disulphide bonds, was synthesized by solution procedure in order to demonstrate the usefulness of our newly developed solvent system, a mixture of dichloromethane or chloroform and trifluoroethanol. The final protected 121-residue peptide was assembled from two large fully protected intermediates, Boc-(1-5 9)-OH and H-(60-121)-OBzl, in CHL/TFE (3:1, v/v) using water-soluble carbodiimide in the presence of HOOBt as coupling reagents. After removal of the protecting groups by HF followed by treatment with Hg(OAc)2 in 50% acetic acid, the fully deprotected peptide was subjected to the oxidative folding reaction. The final product was confirmed to have the correct disulphide structure from its tryptic peptide mapping and to possess the same biological activities as those of the natural product. In order to clarify the active region of the hMK molecule, the N-terminal and C-terminal half domains [(1-59) and (60-121)] were also synthesized by the same procedure used for the hMK synthesis. The C-half domain was confirmed to show the full pattern of bioactivities except for the neuronal cell survival activity, while the N-half one showed much less activity in general.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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