Bioinsecticidal Chymotrypsin DTT EC 3.4.21.1 EC 3.4.21.4 EC 3.4.22.2 ED50 HPLC Insect pests Insecticides Journal Article Ki Kunitz trypsin inhibitor LD50 MALDI-ToF Papain Piptadenia moniliformis Plant Proteins Research Support, Non-U.S. Gov't TCA TFA Trypsin Trypsin Inhibitors dithiothreitol effective dose to inhibit 50% of an enzymatic pool high-performance liquid chromatography inhibition constant lethal dose to kill 50% of an insect population matrix assisted laser desorption ionization time of flight mass spectrometry trichloroacetic acid