Potent fibrinogenolytic protease which cleaves mainly the Aalpha (FGA) and Bbeta (FGB) chains of fibrinogen and slightly the gamma chain (FGG) (PubMed:8193588, PubMed:7488093). Shows preference for substrates having a moderate-size and hydrophobic residue at the P1' position. Preferentially cleaves Ala-|-Leu and Tyr-|-Leu bonds (PubMed:23732127). Is more susceptible to tripeptide inhibitors than TM-3 (AC O57413) (PubMed:9703966). Binds 1 zinc ion per subunit. Inhibited by EDTA and 1,10-phenanthroline (PubMed:8193588). Is also inhibited by endogenous tripeptide inhibitors pyroGlu-Asn-Trp, pyroGlu-Gln-Trp, and pyroGlu-Lys-Trp (PubMed:9703966). Monomer. Expressed by the venom gland. The N-terminus is blocked. Not glycosylated. Belongs to the venom metalloproteinase (M12B) family. P-I subfamily.