Purification of blood coagulation factor V activator from the venom of Iranian Vipera lebetina

The venom of many Viperidae snake appear to contain proteins that affect blood coagulation. The aim of this study was to identify and isolate a blood coagulation factor V activator present in the venom from Vipera lebetina. Factor V activator was purified from 200 mg of crude venom by three steps of chromatorgraphy which included: gel filtration on sephadex G100، Ion exchange chromatography on DEAE and cellulose and affinity chromatography on heparin agarose. The effect of factor V activator on human factor V was studied by measuring the amidiolytic activity of the produced thrombin by activated factor V (Va). The results of SDS – PAGE identified an activator of factor V as a single protein band with a molecular weight of 29 KDa. This compound was converted، in the presence of calcium ions، to active factor Va. It also had arginine esterase activity toward substrate BAEE (-benzoyl arginine ethyester) and a weak amidase activity on S-2222 (benzoyl- le-glu-Gly-Arg-p- nitroanilide). The results of this study showed that the isolated factor is a specific activator on factor V.