| 摘要 |
An assay for screening snake venom for the pres- ence or absence of platelet aggregation inhibitors (PAIs) based on specific receptor binding is described. Using this assay, the identification and characterization of PAIs in a wide range of snake venom samples was accom- plished. The isolated and purified PAI from several of these active snake venoms is described and characterized. In addition, PAIs lacking the Arg-Gly-Asp (RGD) adhesion sequence but containing K* -(G/Sar)-D wherein K* is a modified lysyl residue of the formula R1 2 N(CH2)4CHNHCO- wherein each R1 is independently H, alkyl(1-6C) or at most one R1 is R2-C=NR3 wherein R2 is H, alkyl(1-6C), phenyl or benzyl, or is NR4 2 in which each R4 is independently H or alkyl(1-6C) and R3 is H, alkyl(1-6C), phenyl or benzyl, or R2-C=NR3 is a radical selected from the group consisting of: <IMGS> where m is an integer of 2-3, and each R5 is independently H or alkyl(1-6C); and wherein one or two (CH2) may be replaced by 0 or S provided said O or S is not adjacent to another heteroatom -101- are prepared and shown to specifically inhibit the binding of fibrinogen or von Willebrand Factor to GP IIb-IIIa.
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