Biochemical characterisation of B-glucosidase from the midgut ofAelia acuminataL. (Hemiptera: Pentatomidae)

Aelia acuminata is a wheat injurious bug causing considerable damage to wheat at vegetative growth stage and grain. In this study, some enzymatic properties of β-glucosidase from midgut of A. acuminata were determined. The activity ofβ-glucosidase in the midgut was obtained as 0.122 U/mg protein. Optimal pH for β-glucosidase activity in the midgut was 4.0 and 6.0. The enzyme was considerably stable at different pHs from pH 4.0 to 6.0 for 10 hr. Optimal temperature for β-glucosidase activity in midgut was obtained at 35°C. Increasing the temperature (34 and 44°C) remarkably decreased the stability of the enzyme during 10 days. Activity of the enzyme was retained from 5 to 40°C. Temperatures above 40°C steadily decreased the activity of the enzyme. Activity levels of midgut β-glucosidase was increased with concentrations of Na+, Mg2+, K+ and Ca2+ and decreased in the presence of sodium dodecylsulfate, urea, Cu2+ andTris.