Identification of digestive hydrolases in the larval midgut of the camel nasal bot fly cephalopina titilla tor clark [diptera: Oestridae]

Activities of digestive hydrolases associated with midgut of the third instar larva of Cephalopina titillator were investigated. Based on the hydrolysis of synthetic substrates and optimum pH, it was found that C. titillator midgut contains trypsin-like [optimum pH, 9], chymotrypsin esterase-like [optimum pH, 8], carboxypeptidase A and B [optimum pH at 8.5 and 7 respectively], alkaline- and acidphosphatase [optimum pH at 9 and 5 respectively] and membrane bound leucine aminopeptidase [optimum pH, 8]. An acid proteinase activity was detected, by the ability to hydrolyze acid denaturated haemoglobin; and it seems to be close to pepsin than cathepsin-like enzyme. It has a maximum activity at pH 3.5. alpha-Glucosidase activity, and was also identified [optimum pH at 6] in the midgut, and seems to be membrane bound

Partial characterization of acidic proteinase in the midgut of parasarcophaga surcoufi larvae [Diptera: Sarcophagidae]

Activity of acidic proteinase in the midgut of larval Parasarcophaga surcoufi was investigated and partially characterized. Larval midgut extract showed a moderate acidic pH [pH 4] optimum for hydrolysis of hemoglobin. The proteolytic activity of the larval midgut was estimated by hydrolysis of hemoglobin and was found to be inhibited by pepstatin [aspartic proteinase inhibitor], dithiothreitol [DTT] and mercaptoethanol, while it was not inhibited by soybean trypsin inhibitor [STI] and EDTA. These characteristics may imply that cathepsin D-like proteinase is an effective acidic proteinase present in the Parasarcophaga surcoufi larval midgut