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

Ozgur, Ebru
Yucel, Meral
Öktem, Hüseyin Avni
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.


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To help in the development of Sunn Pest-resistant transgenic plants employing protease or alpha-amylase inhibitors, midgut hydrolytic enzymes of Sunn Pest (Eurygaster integriceps, Put.) (Heteroptera: Scutelleridae) were identified and characterized biochemically. We observed levels of very low proteolytic activity of trypsin (3 nmoles/min/mg), elastase (0.66 nmoles/min/mg) and leucine aminopeptidase-like (14.4 nmoles/min/mg) proteases, but no chymotrypsin and papain-like activity. Proteolytic activities wer...
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Identification and characterization of hydrolytic enzymes of sunn pest (eurygaster integriceps) and cotton bollworm (helicoverpa armigera)
Özgür, Ebru; Öktem, Hüseyin Avni; Department of Biochemistry (2006)
In this study, hydrolytic enzymes from sunn pest (Eurygaster integriceps) and cotton bollworm (Helicoverpa armigera) midguts were identified and characterized in terms of their optimum pH, Km and Vmax values. Hydrolytic activities were also tested for inhibition by several protease and alpha-amylase inhibitors which can be used for the development of insect resistant plants through transgenic technologies. For sunn pest midgut, a low proteolytic activity, belonging mostly to trypsin-like and leucine aminope...
Citation Formats
E. Ozgur, M. Yucel, and H. A. Öktem, “Identification and characterization of hydrolytic enzymes from the midgut of the cotton bollworm, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae),” TURKISH JOURNAL OF AGRICULTURE AND FORESTRY, pp. 285–294, 2009, Accessed: 00, 2020. [Online]. Available: