期刊
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
卷 54, 期 3, 页码 836-842出版社
AMER CHEMICAL SOC
DOI: 10.1021/jf052691u
关键词
Pyrethroid insecticides; pyrethrold-hydrolyzing esterase; molecular characterization; kinetic properties; Klebsiella sp strain ZD112
The gene encoding pyrethroid-hydrolyzing esterase (EstP) from Klebsiella sp. strain ZD112 was cloned into Escherichia coli and sequenced. A sequence analysis of the DNA responsible for the estP gene revealed an open reading frame of 1914 bp encoding for a protein of 637 amino acid residues. No similarities were found by a database homology search using the nucleotide and deduced amino acid sequences of the esterases and lipases. EstP was heterologously expressed in E coli and purified. The molecular mass of the native enzyme was approximately 73 kDa as determined by gel filtration. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the deduced amino acid sequence of EstP indicated molecular masses of 73 and 73.5 kDa, respectively, suggesting that EstP is a monomer. The purified EstP not only degraded many pyrethroid pesticides and the organophosphorus insecticide malathion, but also hydrolyzed p-nitrophenyl esters of various fatty acids, indicating that EstP is an esterase with broad substrates. The Km for trans- and cis-permethrin and k(cat)/K-m values indicate that EstP hydrolyzes both these substrates with higher efficiency than the carboxylesterases from resistant insects and mammals. The catalytic activity of EstP was strongly inhibited by Hg2+, Ag+, and rho-chloromercuribenzoate, whereas a less pronounced effect (3-8% inhibition) was observed in the presence of divalent cations, the chelating agent EDTA, and phenanthroline.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据