characterization of digestive α- and β-glucosidases in the midgut of plagiodera versicolora laicharting (coleoptera: chrysomelidae)

the imported willow leaf beetle, plagiodera versicolora is one of the main pests of forest trees worldwide including iran. activities of α- and β-glucosidases in the midgut of p. versicolora adults were studied in this research. the results showed a higher α- glucosidase activity of adultsthan β-glucosidase. the optimal phs for α- and β-glucosidases activities were found to be 6 and 9, respectively. optimal temperatures for the enzymatic activities were recorded at 30 and 25 °c, respectively. concentration of 0.5 mm k+ significantly minimized the activity of α- glucosidase and maximized the activity of α-glucosidase in presence of ca2+. the activity of β-glucosidase was decreased by adding mg2+ and zn2+. 5 mm concentration of k+ had the most inhibitory impact on β-glucosidase activity, while 0.5 mm concentration of na+ showed the most positive effect on the enzyme activity. the km of midgut α- and β- glucosidase was 0.36 and 2.03 mm and the vmax value was 5.46 and 18.51 μmol/min/mg protein, respectively.