Biochemical characterization of digestive carbohydrases in Moroccan locust, Dociostaurus maroccanus Thunberg (Orthoptera: Acrididae)

The Moroccan locust, Dociostaurus maroccanus (Thunberg), is an agricultural pest which has caused considerable agricultural damage and economic importance. alpha-/beta-Glucosidases and alpha-/beta-Galactosidases are essential enzymes in the carbohydrate digestion of insect pest. Characterization of digestive enzymes is essential for gathering knowledge to production of resistant plants, in this research alpha-/beta-Glucosidases and alpha-/beta-Galactosidase from D. maroccanus. Results showed that the activities of alpha-/beta-Glucosidases were higher than those of alpha-/beta-Galactosidase in digestive system Moroccan locust. Maximum activity for alpha-Glucosidase was at pH 4. Optimum activity for beta-Glucosidases and alpha-/beta-Galactosidase were found at pH 5. The D. maroccanus alpha-/beta-Glucosidases and alpha-/beta-Galactosidases have an optimum temperature activity at 45, 55, 45, and 55 oC, respectively. As calculated using Lineweaver-Burk plots, the Km were about 3.96 +- 0.005, 1.927 +- 0.04, 1.051 +- 0.07, 0.558 +- 0.02 mM for alpha-/beta-Glucosidases and alpha-/beta-Galactosidase, respectively. Fe2+, Hg+, Zn2+, and EDTA inhibited carbohydrases activity, whereas the addition of Mg2+ and K+ increased enzyme activity. The zymogram pattern in the native gel revealed that alpha-/beta-Glucosidases and alpha-/beta-Galactosidases in the digestive system showed 3, 2, 1 and 1 major bands, respectively. Biochemical characterization of digestive carbohydrases is essential for achieving new and safe methods for pest control.