Heterotrimer: blocks the voltage-dependent L-type calcium channels (Cav) from the heart, and the small conductance calcium-activated potassium channels (KCa) in the chromaffin cells and in the brain. Is very toxic to mice. Monomer: serine protease inhibitor that inhibits plasma kallikrein (Ki=0.057 nM), tissue kallikrein (Ki=0.23 nM), trypsin (Ki=0.31 nM), plasmin (Ki=6.1 nM), elastase (Ki=201 nM), factor Xa (Ki=871 nM), alpha-factor XIIa (Ki=2380 nM). Does not inhibit APC, urokinase-type plasminogen activator (uPA/PLAU), tissue plasminogen activator (tPA/PLAT), thrombin and factor VIIa. In addition, the monomer inhibits fibrinolysis in whole blood and prolonged the intrinsec clotting time. Heterotrimer composed of an alpha-neurotoxin-like peptide of 8 kDa (AC P0CJ35), a neurotoxic phospholipase of 16 kDa (AC Q7LZG2) and this serine protease inhibitor of 7 kDa at an approximate stoichiometry of 1:1:4; non-covalently linked. Expressed by the venom gland. LD(50) of the heterotrimer is 50-100 ug/kg to mice. Belongs to the venom Kunitz-type family. Taicatoxin entry