Proteases of Stored Product Insects and Their Inhibition by Specific Protease Inhibitors from Soybeans and Wheat Grain
Annual rept. no. 3 (Final) Nov 1988-Nov 1989
HEBREW UNIV JERUSALEM (ISRAEL)
Pagination or Media Count:
Trypsin-like and chymotrypsin-like enzymes have been identified and separated from the digestive tracts of three model insects the rust red flour beetle Tribolium castaneum, the mealworm Tenebrio molitor and the locust Locusta migratoria. These trypsins and chymotrypsins from legume seeds, such as the Bowman-Birk inhibitor BBI from soybeans and CI from chickpeas. The purified and partially-characterized insect trypsins and chymotrypsins differ significantly from the respective mammalian enzymes in their low content of sulfur-containing amino acids in general and complete lack of disulfide bridges in particular. This suggests a different three-dimensional structure and assembly of the insect digestive proteases. A revised method with high yield for isolation of the labile trypsin-like and chymotrypsin-like enzymes from Tenebrio molitor larval midgut has been worked out. The method is based on affinity chromatography separation on immobilized, synthetic specific inhibitors which have a very low affinity for the respective enzymes in solution. Keywords Enzyme inhibitors, Peptide hydrolases.