Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues

Organophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase (BChE, EC 3.1.1.8), which are both candidates for rapid det...

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Main Authors: Jing-jing TIAN, Xiang-ning CHEN, Yuan-hong XIE, Yong LU, Wen-tao XU, Li XU, Bin DU
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2016-03-01
Series:Journal of Integrative Agriculture
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Online Access:http://www.sciencedirect.com/science/article/pii/S2095311916616507
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author Jing-jing TIAN
Xiang-ning CHEN
Yuan-hong XIE
Yong LU
Wen-tao XU
Li XU
Bin DU
author_facet Jing-jing TIAN
Xiang-ning CHEN
Yuan-hong XIE
Yong LU
Wen-tao XU
Li XU
Bin DU
author_sort Jing-jing TIAN
collection DOAJ
description Organophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase (BChE, EC 3.1.1.8), which are both candidates for rapid detection of organophosphate pesticides. To develop an easy-to-handle method for detecting organophosphate pesticides using BChE, BChE from human was optimized according to the codon usage bias of Pichia pastoris and successfully expressed in P. pastoris GS115. The codon-optimized cDNA shared 37.3% of the codon identity with the native one. However, the amino acid sequence was identical to that of the native human butyrylcholinesterase gene (hBChE) as published. The ratio of guanine and cytosine in four kinds of bases ((G+C) ratio) was simultaneously increased from 40 to 47%. The recombinant hBChE expression reached a total protein concentration of 292 mg mL–1 with an activity of 14.7 U mL–1, which was purified 3.2×103-fold via nickel affinity chromatography with a yield of 68% and a specific activity of 8.1 U mg–1. Recombinant hBChE was optimally active at pH 7.4 and 50°C and exhibited high activity at a wide pH range (>60% activity at pH 4.0 to 8.0). Moreover, it had a good adaptability to high temperature (>60% activity at both 50 and 60°C up to 60 min) and good stability at 70°C. The enzyme can be activated by Li+, Co+, Zn2+ and ethylene diamine tetraacetic acid (EDTA), but inhibited by Mg2+, Mn2+, Fe2+, Ag+ and Ca2+. Na+ had little effect on its activity. The values of hBChE of the Michaelis constant (Km) and maximum reaction velocity (Vm) were 89.4 mmol L–1 and 1721 mmol min–1 mg–1, respectively. The bimolecular rate constants (Ki) of the hBChE to four pesticides were similar with that of electric eel AChE (EeAChE) and higher than that of horse BChE (HoBChE). All values of the half maximal inhibitory concentration of a substance (IC50) for hBChE were lower than those for HoBChE, but most IC50 for hBChE were lower than those for EeAChE except dichlorvos. The applicability of the hBChE was further verified by successful detection of organophosphate insecticide residues in six kinds of vegetable samples. Thus, hBChE heterologously over-expressed by P. pastoris would provide a sufficient material for development of a rapid detection method of organophosphate on spot and produce the organophosphate detection kit.
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spelling doaj-art-72b62bd2ac534bedacc3c9fbec767ffb2025-08-20T03:56:13ZengKeAi Communications Co., Ltd.Journal of Integrative Agriculture2095-31192016-03-0115368469310.1016/S2095-3119(15)61139-XExpression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residuesJing-jing TIAN0Xiang-ning CHEN1Yuan-hong XIE2Yong LU3Wen-tao XU4Li XU5Bin DU6College of Food Science and Engineering, Beijing University of Agriculture, Beijing 102206, P.R. China; TIAN Jing-jing, Mobile: +86-18811582208College of Food Science and Engineering, Beijing University of Agriculture, Beijing 102206, P.R. China; Correspondence CHEN Xiang-ning, Tel/Fax: +86-10-80799174College of Food Science and Engineering, Beijing University of Agriculture, Beijing 102206, P.R. ChinaBeijing Food Safety Monitoring Center, Beijing 100041, P.R. ChinaCollege of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. ChinaCollege of Food Science and Engineering, Beijing University of Agriculture, Beijing 102206, P.R. ChinaCollege of Food Science and Engineering, Beijing University of Agriculture, Beijing 102206, P.R. ChinaOrganophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase (BChE, EC 3.1.1.8), which are both candidates for rapid detection of organophosphate pesticides. To develop an easy-to-handle method for detecting organophosphate pesticides using BChE, BChE from human was optimized according to the codon usage bias of Pichia pastoris and successfully expressed in P. pastoris GS115. The codon-optimized cDNA shared 37.3% of the codon identity with the native one. However, the amino acid sequence was identical to that of the native human butyrylcholinesterase gene (hBChE) as published. The ratio of guanine and cytosine in four kinds of bases ((G+C) ratio) was simultaneously increased from 40 to 47%. The recombinant hBChE expression reached a total protein concentration of 292 mg mL–1 with an activity of 14.7 U mL–1, which was purified 3.2×103-fold via nickel affinity chromatography with a yield of 68% and a specific activity of 8.1 U mg–1. Recombinant hBChE was optimally active at pH 7.4 and 50°C and exhibited high activity at a wide pH range (>60% activity at pH 4.0 to 8.0). Moreover, it had a good adaptability to high temperature (>60% activity at both 50 and 60°C up to 60 min) and good stability at 70°C. The enzyme can be activated by Li+, Co+, Zn2+ and ethylene diamine tetraacetic acid (EDTA), but inhibited by Mg2+, Mn2+, Fe2+, Ag+ and Ca2+. Na+ had little effect on its activity. The values of hBChE of the Michaelis constant (Km) and maximum reaction velocity (Vm) were 89.4 mmol L–1 and 1721 mmol min–1 mg–1, respectively. The bimolecular rate constants (Ki) of the hBChE to four pesticides were similar with that of electric eel AChE (EeAChE) and higher than that of horse BChE (HoBChE). All values of the half maximal inhibitory concentration of a substance (IC50) for hBChE were lower than those for HoBChE, but most IC50 for hBChE were lower than those for EeAChE except dichlorvos. The applicability of the hBChE was further verified by successful detection of organophosphate insecticide residues in six kinds of vegetable samples. Thus, hBChE heterologously over-expressed by P. pastoris would provide a sufficient material for development of a rapid detection method of organophosphate on spot and produce the organophosphate detection kit.http://www.sciencedirect.com/science/article/pii/S2095311916616507butyrylcholinesteraseorganophosphate insecticide residuesPichia pastorisexpressioncodon-optimized
spellingShingle Jing-jing TIAN
Xiang-ning CHEN
Yuan-hong XIE
Yong LU
Wen-tao XU
Li XU
Bin DU
Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
Journal of Integrative Agriculture
butyrylcholinesterase
organophosphate insecticide residues
Pichia pastoris
expression
codon-optimized
title Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
title_full Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
title_fullStr Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
title_full_unstemmed Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
title_short Expression and characterization of a codon-optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
title_sort expression and characterization of a codon optimized butyrylcholinesterase for analysis of organophosphate insecticide residues
topic butyrylcholinesterase
organophosphate insecticide residues
Pichia pastoris
expression
codon-optimized
url http://www.sciencedirect.com/science/article/pii/S2095311916616507
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