Expression of a wheat cytochrome P450 monooxygenase cDNA in yeast catalyzes the metabolism of sulfonylurea herbicides

A wheat cytochrome P450 cDNA (CYP71C6v1) was cloned by RT-PCR and heterologously expressed in yeast. The microsomal fractions derived from this strain could catalyze the metabolism of some sulfonylurea herbicides such as chlorsulfuron, triasulfuron, metsulfuron-metyl, bensulfuron-metyl, and tribenuron-rnetyl, but not sulfonylurea herbicides such as thifensulfuron and pyrazosulfuron. Kinetic parameters K-m for chlorsulfuron and triasulfuron were 57 (+/- 15)mu M and 38 (+/- 16) mu M in vitro, respectively. Analysis of the metabolites demonstrated that the CYP71C6v1 functioned as a 5-phenyl ring hydroxylase when chlorsulfuron and triasulfuron were the substrates. (c) 2005 Elsevier Inc. All rights reserved.