Characterization of a novel pro-coagulant metalloprotease (RVBCMP) possessing alpha-fibrinogenase and tissue haemorrhagic activity from venom of Daboia russelli russelli (Russell's viper): evidence of distinct coagulant and haemorrhagic sites in RVBCMP.

A novel, basic pro-coagulation metalloprotease (Russell's viper basic coagulant metalloprotease, RVBCMP) with an approximate molecular weight of 15kDa was purified from the venom of Daboia russelli russelli (Russell's viper) from eastern India. RVBCMP exerted dose-dependent coagulation of platelet-poor human plasma; however, RVBCMP possessed less coagulant activity as compared with the coagulant activity of crude Russell's viper venom (RVV). RVBCMP did not show oedema induction, direct haemolysis of washed erythrocytes, hydrolysis of human plasma albumin or globulin, and thrombin-like activity, but exhibited caseinolytic, alpha-fibrinogenolytic, and liver tissue haemorrhagic activities. Inhibition of coagulant and protease activities of RVBCMP by EDTA suggested a metalloprotease nature of this protein. RVBCMP showed antigenicity as was evident from the immunoblotting experiment. None of the tested plant extracts, except Leucus lavandulaefolia, inhibited the coagulant or haemorrhagic activity of RVBCMP. Interestingly, aqueous extracts of the tested plants as well as the commercial polyvalent antivenom raised against crude RVV differentially inhibited the coagulant and tissue haemorrhagic activity of RVBCMP. The current investigation provides a fairly good indication that RVBCMP possesses a distinct, perhaps overlapping, site for coagulant and tissue haemorrhagic activity.