Has no significant hemorrhagic activity, but inactivates serpins by limited proteolysis of their reactive-site loops. Cleavage of 1-Phe-|-Val-2, 5-His-|-Leu-6, 14-Ala-|-Leu-15, 15-Leu-|-Tyr-16, and 16-Tyr-|-Leu-17 of insulin B chain. Binds 1 zinc ion per subunit. Monomer. Expressed by the venom gland. Belongs to the venom metalloproteinase (M12B) family. P-I subfamily.