Kunitz-type serine protease inhibitor SOTI (Fragment) 20 ISOTI_SPIOL Trypsin inhibitor Inhibitor of bovine trypsin with a Ki of 2.3 uM. Inhibits 50% of the proteolytic activity of P.rapae larvae midgut extract at a concentration of 20 ug/ml. Inhibitory activity against trypsin is reduced by 43% in the presence of the lysine modifier TBNS, but is not affected by dithiothreitol. TVAACNSPKVGLDSDAELVR