blood coagulation induced by iranian saw-scaled viper (echis carinatus) venom: identification, purification and characterization of a prothrombin activator

objective(s): echis carinatus is one of the venomous snakes in iran. the venom of iranian echis carinatus is a rich source of protein with various factors affecting the plasma protein and blood coagulation factor. some of these proteins exhibit types of enzymatic activities. however, other items are proteins with no enzymatic activity.   materials and methods: in order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. a procoagulant factor (prothrombin activator) was isolated from the venom of the iranian snake echis carinatus with a combination of gel filtration (sephadex g-75), ion-exchange chromatography (deae- sepharose) and reverse phase hplc. furthermore, proteolytic activity of the crude venom and all fractions on blood coagulation factors such as prothrombin time (pt) was studied. results: in the present study, the pt test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). the purified procoagulant factor revealed a single protein band in sds polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kda. a single-band protein showed fragment patterns similar to those generated by the group a prothrombin activators, which convert prothrombin into meizothrombin independent of the prothrombinase complex. conclusion: this study showed that the fraction which separated from iranian snake echis carinatus venom can be a prothrombin activators. it can be concluded that this fraction is a procoagulant factor.