Purification and characterization of a thrombin-like enzyme, elegaxobin, from the venom of Trimeresurus elegans (Sakishima-habu).

A thrombin-like enzyme, named elegaxobin, was purified from the venom of Trimeresurus elegans (Sakishima-habu) by gel filtration on Sephadex G-100, and ion-exchange chromatographies on Q-Sepharose Fast Flow and S-Sepharose Fast Flow. By this procedure, about 8.5 mg of purified enzyme was obtained from 1.1 g of the venom. The purified enzyme showed a single protein band in SDS-polyacrylamide electrophoresis under reducing condition and its molecular weight is 30,000. The specific activity of this enzyme toward tosyl-L-arginine methyl ester (TAME) was 490 TAME units/mg of protein. Elegaxobin clotted only rabbit fibrinogen whereas human and bovine fibrinogens were unaffected. In the fibrinogen-fibrin convertion, the enzyme released only fibrinopeptide A from rabbit fibrinogen, whereas fibrinopeptide B was not released. The N-terminal sequences (Val-Ile-Gly-Gly) of this enzyme was identical to typical sequence of serine proteinases.