Snake venom serine protease that exhibits alpha-fibrinase and beta-fibrinogenase activities. It replaces missing factors VIII (F8) and IX (F9) in deficient plasmas by activating purified human factor X (F10) into factor Xa. It releases serotonin from platelets and induces platelet aggregation in human (but not in rabbit). Has caseinolytic, arginine-esterase and amidase activities. Inhibited by diisopropylfluorophosphate (DFP), benzamidine, heparin and hirudin, but not by plasmatic thrombin inhibitors, antithrombin-III and ecotin. Heterodimer of an alpha and a beta chain. Subunit beta is constituted of two disulfide-linked polypeptidic chains, beta and beta'. Calcium appears to be required for structural cohesion of the molecule. Expressed by the venom gland. Both chains alpha and beta are N-glycosylated. Belongs to the peptidase S1 family. Snake venom subfamily. As the three chains have the same N-terminal sequence, they are merged. The respective apparent molecular mass of the chains are 43000 (alpha), 35500 (beta) and 10200 (beta') as determined by SDS/PAGE under reducing conditions.