| 11396979 |
Lamb DC, Cannieux M, Warrilow AG, Bak S, Kahn RA, Manning NJ, Kelly DE, Kelly SL: Plant sterol 14 alpha-demethylase affinity for azole fungicides. Biochem Biophys Res Commun. 2001 Jun 15;284(3):845-9.
Azole fungicides were thought to have much greater affinity for the fungal cytochrome P450 enzyme, sterol 14 alpha-demthylase (CYP51) than the plant orthologue. Using purified CYP51 from the plant Sorghum bicolor L Moenech, a direct comparison of the sensitivity to the fungicides triadimenol and tebuconazole has been carried out. S. bicolor CYP51 was purified to homogenity as determined by SDS--PAGE and specific heme content. Addition of the azole fungicides triadimenol and tebuconazole induced type II spectral changes, with saturation occurring at equimolar azole/P450 concentrations. Inhibition of reconstituted activities revealed only a threefold insensitivity of the plant CYP51 compared to a fungal CYP51, from the phytopathogen Ustilago maydis, as judged by IC (50) values. The implications for fungicide mode of action and application are discussed. |
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