TRYPSIN AND CHYMOTRYPSIN FROM BEETLE PTEROSTICHUS MELANARIUS

Proteinases from the digestive tract of Pterostichus melanarius Illiger have an optimal activity near pH 8 and 47°C when denatured haemoglobin is used as the substrate. This activity is competitively inhibited by bovine serum and the inhibitor appears to be associated with the α-globulin. Trypsin and chymotrypsin have been demonstrated in the digestive tract by following the hydrolysis of BAEE and BTEE. The two proteinases occur in about equal concentrations in both males and females and have been partially purified and partially separated by ammonium sulphate fractionation, and column chromatography (Sephadex G-75 and G-100 and DEAE cellulose). The molecular weights are estimated to be 16,600 and 20,800 for trypsin and chymotrypsin. Both enzymes appear to be anions at pH 7 on cellulose acetate strips. PMSF inhibits both trypsin and chymotrypsin and TPCK inhibits only the latter. © 1969.