Identification and characterization of hydrolytic enzymes of sunn pest (eurygaster integriceps) and cotton bollworm (helicoverpa armigera)

Özgür, Ebru
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 aminopeptidase-like proteases, and a very high alpha-amylase activity was found in sunn pest midgut, reflecting its high carbohydrate diet. Proteolytic activities could not be inhibited by natural protease inhibitors (SBTI and aprotinin) but inhibited significantly by a general serine protease inhibitor PMSF and metalloprotease inhibitors CdCl2 and CuCl2. alpha-Amylase activity of sunn pest midgut is resistant to inhibition by bean alpha-amylase inhibitor, but inhibited by chickpea, wheat and maize alpha-amylase inhibitors by 26 %, 37 % and 40 %, respectively. For cotton bollworm midgut, a very high proteolytic activity, belonging to serine and metalloprotease type, was detected. alpha-Amylase activity was lower compared to sunn pest midgut, but there were higher and diverse type of proteases, might be reflecting its wide range of host preference. Proteolytic activity was significantly inhibited by both natural protease inhibitors (SBTI and aprotinin). It was also inhibited by several synthetic protease inhibitors (PMSF, E-64, TPCK, CdCl2, CuCl2, Chymostatin). alpha-Amylase activity was inhibited by 60 % by wheat alpha-amylase inhibitor, while maize, chickpea and bean alpha-amylase inhibitors had no effect on cotton bollworm midgut alpha-amylase activity.


MELLATI, AA; YUCEL, M; ALTINORS, N; Gündüz, Ufuk (1993-10-01)
The M2-type pyruvate kinase was purified from human meningioma by ammonium sulfate precipitation, followed by ion exchange and affinity chromatography. The specific activity of the purified enzyme was 33.4 U/mg with a yield of 6.5%.
Preparation of Chitosan-Coated Magnetite Nanoparticles and Application for Immobilization of Laccase
Kalkan, Nuzhet Ayca; AKSOY, SERPİL; Aksoy, Eda Ayse; Hasırcı, Nesrin (2012-01-15)
In this study, immobilization of laccase (L) enzyme on magnetite (Fe(3)O(4)) nanoparticles was achieved, so that the immobilized enzyme could be used repeatedly. For this purpose, Fe(3)O(4) nanoparticles were coated and functionalized with chitosan (CS) and laccase from Trametes versicolor was immobilized onto chitosan-coated magnetic nanoparticles (Fe(3)O(4)-CS) by adsorption or covalent binding after activating the hydroxyl groups of chitosan with carbodiimide (EDAC) or cyanuric chloride (CC). For chitosa...
Identification and characterization of hydrolytic enzymes from the midgut of Sunn Pest of wheat (Eurygaster integriceps)
Ogur, E.; YÜCEL, MUSTAFA; Öktem, Hüseyin Avni (Informa UK Limited, 2009-01-01)
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...
Determination of binary pesticide mixtures by an acetylcholinesterase-choline oxidase biosensor
Kok, FN; Hasırcı, Vasıf Nejat (2004-02-15)
In this study, acetylcholinesterase (AChE) and choline oxidase (ChO) were co-immobilized on poly (2-hydroxyethyl methacrylate) (pHEMA) membranes to construct a biosensor for the detection of anti-cholinesterase compounds. pHEMA membranes were prepared with the addition of SnCl4 to achieve the desired porosity. Immobilization of the enzymes was done by surface attachment via epichlorohydrin (Epi) and Cibacron Blue F3G-A (CB) activation. Enzyme immobilized membrane was used in the detection of anti-cholineste...
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 (2009-01-01)
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, differen...
Citation Formats
E. Özgür, “Identification and characterization of hydrolytic enzymes of sunn pest (eurygaster integriceps) and cotton bollworm (helicoverpa armigera),” Ph.D. - Doctoral Program, Middle East Technical University, 2006.