PURIFICATION AND MOLECULAR-CLONING OF A PLATELET-AGGREGATION INHIBITOR FROM THE SNAKE (AGKISTRODON HALYS BREVICAUDUS) VENOM

A platelet glycoprotein IIb-IIIa (GP IIb-IIIa) antagonist, salmosin, w as purified to homogeneity from Korean snake (Agkistrodon halys brevic audus) venom by means of chromatographic fractionations. We have isola ted the cDNA encoding salmosin by using the cDNA library of the snake venom gland and analyzed its complete nucleotide sequence, The molecul ar identity was confirmed by comparison of the deduced amino acid sequ ence with the directly determined primary structure of salmosin, This protein is a single-chain polypeptide composed of 73 amino acids inclu ding 12 cysteines as well as the sequence Arg-Gly-Asp, a proposed reco gnition site of adhesive proteins. The primary sequence of salmosin sh ows considerable homology to previously described proteins of snake ve nom GP IIb-IIIa antagonist family. A molecular mass of 7474 for the pr otein was determined by matrix-assisted laser desorption ionization ma ss spectrom-etry, Salmosin inhibits GP IIb-IIIa binding to immobilized fibrinogen with an IC50 Of 2.2 nM and ADP-induced platelet aggregatio n with an IC50 Of 131 nM, respectively. This work demonstrates the pur ification, characterization, and cDNA cloning of salmosin, a platelet aggregation inhibitor that may have therapeutic potential as an antith rombotic agent, (C) 1998 Elsevier Science Ltd.