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

Authors

EBRU ÖZGÜR
MERAL YÜCEL
HÜSEYİN AVNİ ÖKTEM

DOI

10.3906/tar-0802-5

Abstract

Midgut hydrolytic enzymes of Helicoverpa armigera Hübner (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 a-amylase inhibitors on them.

Keywords

Helicoverpa armigera, protease, protease inhibitors, α-amylase, \alpha-amylase inhibitors

First Page

285

Last Page

294

Recommended Citation

ÖZGÜR, EBRU; YÜCEL, MERAL; and ÖKTEM, HÜSEYİN AVNİ (2009) "Identification and characterization of hydrolytic enzymes from the midgut of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)," Turkish Journal of Agriculture and Forestry: Vol. 33: No. 3, Article 7. https://doi.org/10.3906/tar-0802-5
Available at: https://journals.tubitak.gov.tr/agriculture/vol33/iss3/7