Identification and characterization of hydrolytic enzymes from the midgut of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Authors : Ebru ÖZGÜR, Meral YÜCEL, Hüseyin Avni ÖKTEM

Pages : 285-294

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Publication Date : 2009-06-01

Article Type : Research Paper

Abstract :Midgut hydrolytic enzymes of Helicoverpa armigera Hübner insert ignore into journalissuearticles values(Lepidoptera: Noctuidae); were identified and partially characterized. Km, Vmax, optimum pH, and specific activity were determined for proteolytic enzymes and a-amylases. All hydrolytic enzyme activity had an optimum pH value in the alkaline pH range. We observed major serine protease activity, together with minor cysteine-like activity, the former being significantly inhibited by soybean trypsin inhibitor insert ignore into journalissuearticles values(SBTI); and aprotinin. Moreover, different degrees of inhibition were observed with synthetic protease inhibitors. Electrophoretic methods revealed 3 isozymes of a-amylases, of which 2 had higher molecular weight and were more active than the other. Inhibition of amylolytic activity was observed with wheat a-amylase inhibitor insert ignore into journalissuearticles values(WAAI);, whereas partially purified maize, chickpea, and bean seed crude extracts did not exhibit inhibitory activity toward a-amylases. To the best of our knowledge this is the first report on the properties of a-amylases from Helicoverpa armigera and the effects of several plant-originated a-amylase inhibitors on them.
Keywords : Helicoverpa armigera, protease, protease inhibitors, α amylase, a amylase inhibitors