Inhibition of plant protoporphyrinogen oxidase by the herbicide acifluorfen-methyl.
نویسندگان
چکیده
The effect of acifluorfen-methyl on tetrapyrrole synthesis in greening chloroplasts of Cucumis sativus was examined. Formation of Mg-proto-porphyrin IX from delta-aminolevulinate was reduced 98% by 10 micromolar acifluorfen-methyl. Conversion of protoporphyrin IX to Mg-protoporphyrin IX was unaffected, but protoporphyrin IX synthesis from delta-aminolevulinate was blocked, indicating a site of inhibition prior to the Mg-chelatase. The enzymic oxidation of protoporphyrinogen IX to protoporphyrin IX was highly sensitive to acifluorfen-methyl, indicating that the site of action of the herbicide is the protoporphyrinogen oxidase. ((c) 1989 FMC Corporation. All rights reserved.).
منابع مشابه
Kinetic studies on protoporphyrinogen oxidase inhibition by diphenyl ether herbicides.
Diphenyl ethers (DPEs) and related herbicides are powerful inhibitors of protoporphyrinogen oxidase, an enzyme involved in the biosynthesis of haems and chlorophylls. The inhibition kinetics of protoporphyrinogen oxidase of various origins by four DPEs, (methyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen and its methyl ester, acifluorfen-methyl), methyl-5-[2-chloro...
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Protoporphyrinogen oxidase, the molecular target of diphenylether-type herbicides, was purified to homogeneity from yeast mitochondrial membranes and found to be a 55-kDa polypeptide with a pI of 8.5 and a specific activity of 40,000 nmol of protoporphyrin/h/mg of protein at 30 degrees C. The Michaelis constant (Km) for protoporphyrinogen IX was 0.1 microM. Due to the high affinity of the enzym...
متن کاملLocalization within chloroplasts of protoporphyrinogen oxidase, the target enzyme for diphenylether-like herbicides.
Plant protoporphyrinogen oxidase is of particular interest since it is the last enzyme of the common branch for chlorophyll and heme biosynthetic pathways. In addition, it is the target enzyme for diphenyl ether-type herbicides, such as acifluorfen. Two distinct methods were used to investigate the localization of this enzyme within Percoll-purified spinach chloroplasts. We first assayed the en...
متن کاملProtoporphyrinogen oxidase as a molecular target for diphenyl ether herbicides.
Diphenyl ether herbicides induce an accumulation of protoporphyrin IX in plant tissues. By analogy to human porphyria, the accumulation could be attributed to decreased (Mg or Fe)-chelatase or protoporphyrinogen oxidase activities. Possible effects of acifluorfen-methyl on these enzymes were investigated in isolated corn (maize, Zea mays) etioplasts, potato (Solanum tuberosum) and mouse mitocho...
متن کاملEffects of Acifluorfen on Endogenous Antioxidants and Protective Enzymes in Cucumber (Cucumis sativus L.) Cotyledons.
The herbicide acifluorfen (2-chloro-4-(trifluoromethyl)phenoxy-2-nitrobenzoate) causes strong photooxidative destruction of pigments and lipids in sensitive plant species. Antioxidants and oxygen radical scavengers slow the bleaching action of the herbicide. The effect of acifluorfen on glutathione and ascorbate levels in cucumber (Cucumis sativus L.) cotyledon discs was investigated to assess ...
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ورودعنوان ژورنال:
- Plant physiology
دوره 90 4 شماره
صفحات -
تاریخ انتشار 1989