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Younis HM, Mohanty P: Inhibition of electron flow and energy transduction in isolated spinach chloroplasts by the herbicide dinoseb. Chem Biol Interact. 1980 Oct;32(1-2):179-86.
The mode of action of dinoseb (2-sec-butyl-4-6-dinitrophenol) on chloroplast reactions was studied. Electron flow from water or from an artificial electron donor, diphenylcarbazide (DPC), to dichlorophenol indophenol (DCPIP) was inhibited at low concentrations of the herbicide (5--10 microM) suggesting a site for dinoseb inhibition at the oxidizing side of photosystem II (PS II). Ferricyanide photoreduction was also inhibited by dinoseb. Cyclic and non-cyclic photophosphorylation and Mg2+-ATPase activity were inhibited by dinoseb, which indicates that this herbicide also acts as an energy transfer inhibitor. Among the above mentioned activities, non-cyclic photophosphorylation was the most sensitive to the inhibition by dinoseb. Ca2+-ATPase activity of solubilized heat activated chloroplast coupling factor 1 (CF1) was stimulated by dinoseb. However, the same activity was inhibited in chloroplasts, which perhaps reflect a difference in the mode of interaction of dinoseb with solubilized and membrane bound coupling factor. |
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