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

Date

2009-01-01

Author

Ozgur, Ebru
Yucel, Meral
Öktem, Hüseyin Avni

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Midgut hydrolytic enzymes of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) were identified and partially characterized. K-m, V-max, optimum pH, and specific activity were determined for proteolytic enzymes and alpha-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 (SBTI) and aprotinin. Moreover, different degrees of inhibition were observed with synthetic protease inhibitors. Electrophoretic methods revealed 3 isozymes of alpha-amylases, of which 2 had higher molecular weight and were more active than the other. Inhibition of amylolytic activity was observed with wheat alpha-amylase inhibitor (WAAI), whereas partially purified maize, chickpea, and bean seed crude extracts did not exhibit inhibitory activity toward alpha-amylases. To the best of our knowledge this is the first report on the properties of alpha-amylases from Helicoverpa armigera and the effects of several plant-originated alpha-amylase inhibitors on them.

Subject Keywords

Helicoverpa armigera, Protease, Protease inhibitors, Alpha-amylase, Alpha-amylase inhibitors

URI

https://hdl.handle.net/11511/39226

Collections

Department of Biology, Article