%0 Journal Article
%T Determination of the Catalytic Structures of Methyl Parathion Hydrolase<br>甲基对硫磷水解酶参与催化相关结构的研究
%A WU Xu-Ping
%A LIU Wei-Dong
%A CAO Hui
%A LI Shun-Peng
%A CUI Zhong-Li
%A <br>吴旭平
%A 刘卫东
%A 曹慧
%A 李顺鹏
%A 崔中利
%J 生物工程学报
%D 2005
%I 
%X Methyl parathion hydrolase (MPH) is a novel member of organophosphorus hydrolase. In this study, mpd gene was expressed in Escherichia coli DH5alpha with its native promoter. MPH was purified to homogeneity. Results show that metal-chelating compounds cannot inhabit the enzyme activity. Inductively Coupled Plasma-Atomic Emission Spectrometry analysis showed that MPH is a zinc-containing enzyme, the Zinc to enzyme molar ratio is near 2:1. In order to investigate critical residues related to enzymatic activity of MPH, chemical modification reagents EDC, DEPC, butanedione and pyridoxal were tested. Experiment results suggested that aspartate, glutamate, arginine and lysine are not important for enzyme activity. But DEPC, which can modify histidine residue, inactivate the enzyme activity greatly, and the inactivation rate is 9.6 h(-1). This result reflects that histidine residues are essential for enzyme activity. All these results provide basic data for MPH structure and molecular evolution research.
%K methyl parathion hydrolase
%K metal ion content
%K chemical modification
%K critical residue amino acids<br>甲基对硫磷水解酶，
%K 金属离子含量，
%K 化学修饰，
%K 必需氨基酸
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=A66E90C274451689E69F6F0291467824&aid=FA033AB4866D678E&yid=2DD7160C83D0ACED&vid=659D3B06EBF534A7&iid=B31275AF3241DB2D&sid=EAA944F99AA73B33&eid=15A3E3A739C4EF3F&journal_id=1000-3061&journal_name=生物工程学报&referenced_num=1&reference_num=22