| 15627243 |
Xiang WS, Wang XJ, Ren TR, Ju XL: Expression of a wheat cytochrome P450 monooxygenase in yeast and its inhibition by glyphosate. Pest Manag Sci. 2005 Apr;61(4):402-6.
Glyphosate is a non-selective herbicide which acts by inhibiting 5-enolpyruvylshikimate-3-phosphate synthase. Wheat cytochrome P450 monooxygenase specifically catalyzes the metabolism of some sulfonylurea herbicides such as chlorsulfuron and triasulfuron. Here we report that glyphosate is an inhibitor of a wheat cytochrome (CYP71C6v1), the cDNA of which was amplified by RT-PCR and heterologously expressed in yeast. The microsomal fractions derived from this strain had a Soret peak at 502 nm in the reduced carbon monoxide difference spectrum, which is a typical spectral characteristic. The addition of glyphosate to the microsomal protein resulted in a Type II spectrum indicative of binding via the nitrogen group to haem of cytochrome P450 as a sixth ligand. A spectral dissociation constant, K (s) of 70 micromol litre (-1) was observed and an IC50 of 11 micromol litre (-1) was found for glyphosate inhibition of CYP71C6v1 P450 activity. |
82(1,1,1,2) |