Digestive proteases of Papilio demoleus : Compartmentalization and characterization

Digestive proteolytic activities were studied in the larval midgut of Papilio demoleus by using azocasein, specific substrates and inhibitors regarding enzymatic allocation in the alimentary canal. The highest proteolytic activity was found in the midgut rather than foregut and hindgut that highest proteolytic activity was observed in soluble fraction. All specific proteases were almost equally distributed in both the anterior and posterior midgut except for trypsin- and chymotrypsin-like proteases, which showed the highest activity in the anterior midgut. Two peaks were observed in alkaline and acidic pHs when general proteolytic activities were assayed using azocasein in soluble and membrane-bound fractions. Specific substrates revealed the presence of trypsin-like, chymotrypsin-like, elastase, cathepsins B and L as well as two exopeptidases. These findings were confirmed using specific inhibitors including PMSF, TLCK, TPCK, SBTI, cystatin, DTT, E-64, EDTA and phenanthroline. Determination and characterization of the insect’s digestive proteases will enable development of pest control by designing protease inhibitors. This procedure will help us to designate an efficient pest control method with the lowest impact on the environment.