Inhibits trypsin with a Ki of 0.25 uM. Inhibits the trypsin-like proteases in midguts of larval H.armigera, S.exigua, and P.rapae. Stable from pH 2.0 to 12.0. Retains almost 100% of its activity after heating for 10 minutes at 70 degrees Celsius, activity is lost rapidly above 70 degrees Celsius. Heterodimer of an alpha and a beta chain linked by a disulfide bond. The reactive bond is likely to include a lysine residue. Belongs to the protease inhibitor I3 (leguminous Kunitz-type inhibitor) family. The order of the peptides shown is unknown.