ABSTRACT
Snake venom particulary those belonging to Crotalidae and viperidae families, are known to contain number of components affecting blood coagulation. The Aim of this paper is to describe the isolation a specific blood coagulation factor X activator from the crude venom of Iranian Vipera lebetina. Factor X activator was purified from two hundred mg of crude venom by gel filtration on sephadex G-100 and two step ion-exchange chromatography on DEAE-cellulose [DEAE-52]. It showed a single band in sodium dodecyl sulfate-polyacrylamid gel electrophoresis [SDS-PAGE] in non-reducing condition. The mol. wt was estimated to be 78000Da by SDS-PAGE the activator, activated factor X to Xa in presence of calcium ions. It could not activate prothrombin, no had effect an fibrinogen and thus appeared to act specifically on factor X. The activator no amidolytic activtiy on factor Xa substrate benzoyl-Ile-glu-Gly-Arg-p-nitracnilide [S-2222]. It had no arginine esterase activity toward substrate benzoylagrinine ethylester [BAEE] while crude venom hydrolyzes this substrate. The results of this study showed that The activator do act specifically on factor X