Catalytic characteristics of plant-esterase from wheat flour.
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.
Key Laboratory of Biorheology Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Shazheng Ave. 174, Chongqing, 400030, People's Republic of China. houcj@cqu.edu.cn
Chang-jun
CJ
Hou
Kun
K
He
Li-min
LM
Yang
Dan-qun
DQ
Huo
Mei
M
Yang
Shun
S
Huang
Liang
L
Zhang
Cai-hong
CH
Shen
D001562:Benzimidazoles / Q000494:pharmacology; D001974:Bromosuccinimide / Q000494:pharmacology; D002219:Carbamates / Q000494:pharmacology; D002235:Carbofuran / Q000494:pharmacology; D002384:Catalysis; D004006:Dichlorvos / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004950:Esterases / Q000737:chemistry / Q000378:metabolism*; D005433:Flour; D006863:Hydrogen-Ion Concentration; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D014908:Triticum / Q000201:enzymology*
D001562:Benzimidazoles; D002219:Carbamates; D010940:Plant Proteins; D004006:Dichlorvos; D004950:Esterases; C006698:carbendazim; D001974:Bromosuccinimide; D002235:Carbofuran