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-metyl, but not sulfonylurea herbicides such as thifensulfuron and pyrazosulfuron. Kinetic parameters Km for chlorsulfuron and triasulfuron were 57 (±15) μM and 38 (±16) μM 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.