Activity of carboxylesterase enzyme in different tissues of sixth instar larvae Orthaga exvinacea Hampson under various conditions of temperature and pH

Abstract

The mango leaf-webber, Orthaga exvinacea Hampson is one of the major pests of mango crop. In larval stage, they defoliate the leaves and thereby reduce the crop yield but in adult stage, they do not cause any damage to the crop. Insect must chemically alter and dispose of a large variety of compounds to maintain their normal body function. They must neutralise, inactivate or eliminate many foreign substances including pesticides. All foreign organic compounds are susceptible to metabolic attack in vivo. This biotransformation may involve by the activity of some enzymes. Carboxylesterases are major enzymes involved in the resistance process in several insect species. The appraisal and hydrolytic capacity of these catalysts work best inside particular temperature and hydrogen ion concentration (pH) conditions. The impacts of temperature and pH on the hydrolysis of both α-naphthyl acetate and β-naphthyl acetate by Orthaga exvinacea carboxylesterase and the tissue fractionation of these enzymes were examined. The ideal conditions for measuring carboxylesterase movement of Orthaga exvinacea were pH of 6.6 - 7.2 and temperature 35°C - 45°C. The particular carboxylesterase action indicates most extreme behaviour at pH 6.8 and temperature at 40oC. Tissue confinement investigation of the enzyme in Orthaga exvinacea demonstrated the nearness of carboxylesterase action in every division.