Purification and characterization of phenoloxidase from the hemocytes of Eurygaster integriceps (Hemiptera: Scutelleridae)

Zibaee, Arash; Bandani, Ali Reza; Malagoli, Davide

doi:10.1016/j.cbpb.2010.10.006

Cited by 33 publications

(37 citation statements)

References 43 publications

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“…pH optimum and stability pH has significant effect on enzyme activity (Zibaee et al 2011) in many catalytic reactions. Plant-esterase showed 90% initial activity from pH 5.5 to pH 7.0, with an optimum at pH 6.5 (Fig.…”

Section: Temperature Optimum and Stabilitymentioning

confidence: 99%

Catalytic characteristics of plant-esterase from wheat flour

Hou

Yang

et al. 2011

World J Microbiol Biotechnol

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A plant-esterase extracted from wheat flour and purified with a PEG1000/NaH(2)PO(4) aqueous two-phase system was characterized for its catalytic characteristics. The optimal condition for plant-esterase to catalyze 1-naphthyl acetate was at 30°C, pH 6.5. It kept stability at 20°C during 120 min and at pH 5.5 during 60 h. The effects of metal ions, chemical modification reagents and pesticides on plant-esterase activity were investigated. It was found that Ba(2+) and Pb(2+) at concentrations of 20 mM significantly inhibited the activity of plant-esterase while Mg(2+), Ca(2+) and Fe(2+) at the same concentration enhanced the enzyme activity. Chemical modification reagents significantly influenced the activity of plant-esterase. Particularly, PMSF (4.5 mM) and N-bromosuccinimide (11 mM) inhibited by 5.40-19.87% of the enzyme activity. It is implied that serine and tryptophan are related to the enzyme activity. Plant-esterase were displayed concentration-dependent inhibition by dichlorvos, carbofuran and carbendazim (IC50 = 0.31-63.12 ppm). All these results indicated that catalytic efficiency of plant-esterase strongly depends on reaction conditions, activity effectors and amino acid residues at the active site. It makes meaningful guidance on further design of sensing material in monitoring pesticides.

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Section: Temperature Optimum and Stabilitymentioning

confidence: 99%

Catalytic characteristics of plant-esterase from wheat flour

Hou

Yang

et al. 2011

World J Microbiol Biotechnol

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“…The quinones produced by PO undergo a series of additional enzymatic and non-enzymatic reactions leading to polymerization and melanin synthesis in the final stages of nodulation and encapsulation against invading microorganisms (Zibaee et al, 2011). In fact, insect PO are synthesized as zymogens called pro PO which are activated by proteolytic cleavage at a specific site in response to infection or wounding (Cerenius & Söderhall, 2004).…”

Section: Effect Of Botanical Insecticides On Nodule Formation and Phementioning

confidence: 99%

“…Lineweaver-Burk plots analysis of PO activity after treating insects by plant extract revealed an inhibition on enzyme activity by decreasing V max value and increasing K m one. Since the K m has an inverse relationship with the substrate concentration required to saturate the active sites of the enzyme, this indicates decreased enzyme affinity for substrate (Zibaee et al, 2011). In other words, K m is the measurement of the stability of the enzyme-substrate complex and a high K m would indicate weak binding and a low K m strong binding.…”

Section: Effect Of Botanical Insecticides On Nodule Formation and Phementioning

confidence: 99%

“…Although it is possible for mixed-type inhibitors to bind in the active site, this type of inhibition generally results from an allosteric effect where the inhibitor binds to a different site on an enzyme. Inhibitor binding to this allosteric site changes the conformation (i.e., tertiary structure e or three-dimensional shape) of the enzyme so that the affinity of the substrate for the active site is reduced (Zibaee et al, 2011).…”

Section: Effect Of Botanical Insecticides On Nodule Formation and Phementioning

confidence: 99%

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Botanical Insecticides and Their Effects on Insect Biochemistry and Immunity

Zibaee¹

2011

Pesticides in the Modern World - Pests Control and Pesticides Exposure and Toxicity Assessment

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“…The processes need careful attention since the enzyme is unstable and rapid loss of enzymatic activity may occur during purification process. So far, proPO has been purified and characterized from some insect species including Hemiptera, Lepidopteran, Dipteran, Blattodea and Orthoptera 7 . Hence, objectives of the current study are (i) extraction and purification of PO from hemocytes of E. kuehniella larvae, (ii) determination of enzymatic parameters by using different substrates, pH, temperature and chelating agents, (iii) determining the effect of two insect growth regulators and (iv) extraction of an endogenous inhibitor from hemolynph of the larvae.…”

Section: Introductionmentioning

confidence: 99%

Purification and characterization of a phenoloxidase in the hemocytes ofEphestia kuehniellaZeller (Lepidoptera: Pyralidae): effects of insect growth regulators and endogenous inhibitors

Delkash-Roudsari

Zibaee

Bigham

2014

Journal of Enzyme Inhibition and Medicinal Chemistry

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A phenoloxidase was extracted and purified from hemocytes of Ephestia kuehniella by using ammonium sulfate, Sepharyl G-100 and DEAE-Cellulose fast flow chromatographies. At the final stage of purification, a protein was purified by molecular mass of 78.5 kDa, specific activity of decreased activity of the purified PO but Ca 2+ and Cu 2+ increased the enzymatic activity. EDTA (General chelating agent), DTC (Copper chelating agent) and EGTA (Calcium chelating agent) significantly decreased PO activity but TTHA (Magnesium chelating agent) showed no statistically significant effects. Kinetic parameters of the purified enzyme showed the highest V max when L-DOPA was used as substrate but no significant differences were observed in case of K m for used L-DOPA, pyrocatechol and hydroquinone. In vitro inhibition of the purified PO by using two insect growth regulators, Hexaflumuron and Pyriproxyfen, revealed IC 50 of 96.41 and 38.59 mg/ml for these compounds, respectively. Kinetic studies using different concentrations of L-DOPA and IC 50 concentrations of the two IGRs revealed the increase of K m value versus control and competitive inhibition. Finally, column chromatography of hemolymph revealed peak III showing endogenous inhibitors of phenoloxidase by molecular weight of 27.3 that showed competitive inhibition on the PO.

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Purification and characterization of phenoloxidase from the hemocytes of Eurygaster integriceps (Hemiptera: Scutelleridae)

Cited by 33 publications

References 43 publications

Catalytic characteristics of plant-esterase from wheat flour

Catalytic characteristics of plant-esterase from wheat flour

Botanical Insecticides and Their Effects on Insect Biochemistry and Immunity

Purification and characterization of a phenoloxidase in the hemocytes ofEphestia kuehniellaZeller (Lepidoptera: Pyralidae): effects of insect growth regulators and endogenous inhibitors

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