| | 1 | Author
| DonaldE. Moreland, FrederickT. Corbin, WilliamP. Novitzky, CarolE. Parker, KennethB. Tomer | Requires cookie* | | | Title
| Metabolism of Metolachlor by a Microsomal Fraction Isolated from Grain Sorghum ( Sorghum bicolor) Shoots  | | | | Abstract
| A microsomal fraction isolated from the shoots of 3-to 4-day-old, dark-grown, grain sor ghum (Sorghum bicolor cv. Funk G 522 D R) seedlings was characterized. The preparations had a cytochrome P-450 content that varied from approximately 90 to 150 pmol P-450/mg protein with cytochrome P-420 varying from 0 to 3% of the P-450 content. Type I difference spectra were formed with cinnamic acid and metolachlor, and a type II spectrum was formed with tetcyclacis. In short-term assays with [14C]metolachlor as substrate, the preparations produced a single time-dependent product that separated on silica gel TLC plates developed in benzene/ acetone (2:1, v/v). R F values for metolachlor and the metabolite were approximately 0.70 and 0.48, respectively. The microsomal reaction required N A D PH and oxygen, and was inhibited by carbon monoxide, with the inhibition being partially reversed by actinic light. Compounds known to inhibit the activity of cytochrome P-450 monooxygenases (piperonyl butoxide, tet cyclacis, and tridiphane) also prevented formation of the metabolite. Identity of the metabolite was confirmed by TLC and positive ion thermospray LC/MS to be 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-hydroxy-l-methylethyl)acetamide. Hence, the reaction catalyzed by the sorghum microsomes involved O-demethylation of the methoxypropyl side chain of meto lachlor. | | | |
Reference
| Z. Naturforsch. 45c, 558—564 (1990); received November 9 1989 | | | |
Published
| 1990 | | | |
Keywords
| Microsomes, Metolachlor, Cytochrome P-450, Mixed Function Oxidase, Herbicide Metabolism | | | |
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| ZNC-1990-45c-0558 | | | | Volume
| 45 | |
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