Serine protease inhibitor that inhibits trypsin. Exhibits an anti-tumor effect and displays integrin inhibitory activity without being cytotoxic. Is able to dose-dependently inhibit the adhesion, migration and invasion of human glioblastoma U87 cells. Also impairs the function of alphavbeta3 and to a lesser extent, the activity of alphavbeta6, alphavbeta5, alpha1beta1 and alpha5beta1 integrins. Monomer. Expressed by the venom gland. Average mass. Does not inhibit chymotrypsin. When intracerebroventricularly injected into mice, does not cause any toxic symptoms until a dose of 2 ug. Belongs to the venom Kunitz-type family.