Biochemical characterization of α- and β-glucosidase in digestive system of Agriolimax agrestis L. (Stylommatophora: Limacidae)

The grey field slug, Agriolimax agrestis L. is a pest of vegetable in northern provinces of Iran. Pest digestive enzymes are excellent targets for pesticide agents such as inhibitors. The digestive enzyme inhibitors are used for producing transgenic plants resistant to pests. To achieve this goal, it is necessary to find the nature and properties of these enzymes. In this research, the biochemical properties of α- and β-glucosidase in different parts of digestive system of A. agrestis were investigated. Results showed that the specific activity of β-glucosidases in intestine was higher than its activity in digestive glands. The optimal pH for α- glucosidase activities were 6, 5-6 and 6-7 in front parts of digestive system (esophagus and buccal bulb), intestine and digestive glands, respectively. Also, optimum pH for β- glucosidases activities were obtained as 5, 6 and 4-6 in front parts of digestive system, intestine and digestive glands, respectively. High α- glucosidases activities were found at temperature 60 °C. Also, the optimal temperature for β- glucosidases activities were 40, 50-60 and 50 °C in front parts of digestive system, intestine and digestive glands,, respectively. Estimation of kinetic parameter showed that Km values of the α-glucosidases in the front parts of digestive system, intestine and digestive glands were 2.44, 1.44 and 3.28 mM, respectively and Km values of the β-glucosidases in the front parts of digestive system, intestine and digestive glands were obtained as 1.24, 1.17 and 0.94 mM, respectively. Zymogram pattern in the native gel revealed that A. agrestis α- and β-glucosidase from digestive glands had one and two isoforms, respectively.