ABSTRACT To investigate interaction between proteinaceous extracts of three Iranian wheat cultivars and digestive enzymes of Sunn pest, a population of adult insects was collected in summer from a wheat field located in Borkhar Region, Isfahan, Iran. Seed proteins were extracted by 0.15 M NaCl solution and partially purified using ammonium sulphate. Spectrophotometric assays were implemented to determine enzyme activities. Results indicated cultivar- and dosedependent efficacy of seed protein extracts. Inhibition percentages of a-amylase, a-glucosidase, b-glucosidase and proteolytic activities at concentration of 32 lg/mL and saturation percentage of 70% ammonium sulphate were 54, 37, 25 and 59% by Hamoon, 16, 28, 18 and 19% by Karkheh and 15, 16, 15 and 23% by Dena, respectively. Zymography also confirmed the effect of inhibitors on a-amylase activity. Among wheat cultivars, Hamoon has the highest biological activity against Sunn pest major digestive enzymes and could contribute towards the development of new insect pest control strategies.
