Thrombin-like snake venom serine protease, that cleaves alpha-chain of fibrinogen (FGA) releases only fibrinopeptide A. Shows coagulant, esterase and amidase activities. Induces the barrel rotation syndrome in mice, which is manifested by gyroxin-like, rapid rolling motions. May also reversibly increase the permeability of the blood brain barrier (BBB) in mice. Selective cleavage of Arg-|-Xaa bond in fibrinogen, to form fibrin, and release fibrinopeptide A. The specificity of further degradation of fibrinogen varies with species origin of the enzyme. Inhibited competitively by amidines and guanidines, and irreversibly inhibited by diisopropylfluorophosphate. Monomer. Expressed by the venom gland. Does not have phospholipase activity, does not aggregate platelet, and does not affect the release of the neurotransmitters dopamine and acetylcholine in the nervous system. Belongs to the peptidase S1 family. Snake venom subfamily.