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


Ozgur E., Yucel M., ÖKTEM H. A.

TURKISH JOURNAL OF AGRICULTURE AND FORESTRY, cilt.33, sa.3, ss.285-294, 2009 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 33 Konu: 3
  • Basım Tarihi: 2009
  • Doi Numarası: 10.3906/tar-0802-5
  • Dergi Adı: TURKISH JOURNAL OF AGRICULTURE AND FORESTRY
  • Sayfa Sayıları: ss.285-294

Özet

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.