Prothrombin (F2) activator that is cofactor-independent. Also has fibrinolytic and fibrinogenolytic activity. It degrades the Aalpha-chain and more slowly the Bbeta-chain of fibrin and fibrinogen, while the gamma-chain is only partially and slowly affected. A dose-dependent procoagulant activity is shown in human plasma. Binds 1 zinc ion per subunit. Completely inhibited by EDTA and EGTA. Partially inhibited by serine proteinase inhibitors PMSF and benzamidine. Not inhibited by cysteine proteinase inhibitors mercury ions and E-64. Is active without cofactors, although the presence of low concentrations of calcium and zinc ions enhanced its ability to convert prothrombin (F2) into active thrombin. Optimum pH is 8.0. Monomer. Expressed by the venom gland. Does not present direct thrombin-like or amidolytic activities. Belongs to the venom metalloproteinase (M12B) family. P-I subfamily.