Neurotoxin T1-2 is a presynaptic neurotoxin of the venom that exhibits indirect hemolytic activity against human erythrocytes. The B chain is homologous to venom basic protease inhibitors but has no protease inhibitor activity and is non-toxic. Heterodimer; disulfide-linked. The A chains have phospholipase A2 activity and the B chains show homology with the basic protease inhibitors. Expressed by the venom gland. LD(50) is 0.22 mg/kg by intravenous injection in mice. Belongs to the venom Kunitz-type family.