Methyl Viologen-Dependent Cyclic Electron Transport in Spinach Chloroplasts in the Absence of Oxygen

概要

論文の詳細を見る
The methyl viologen (MV)-dependent, linear electron flow from PS II to PS I was severely blocked in intact or broken, uncoupled chloroplasts when oxygen was removed from the suspension medium, as revealed by measurements of chlorophyll fluorescence and the rate of photo-reduction of MV. Kinetics of the reduction of pre-oxidized P700 by a saturating light pulse showed that reduced MV in the absence of oxygen re-reduces P700^+ via the intersystem electron transport chain. Since the re-reduction of P700^+ was inhibited by 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, the MV-mediated cyclic electron flow, in contrast to the phenazine methosulphate-catalyzed one, involves the plastoquinone pool. However, 2-n-heptyl-4-hydroxyquinoline-N-oxide, 2-n-nonyl-4-hydroxyquinoline-N-oxide and antimycin A did not inhibit the MV-mediated flow. Thus, the inhibition of the linear electron flow in chloroplasts under anaerobic conditions suggested the overreduction of the plastoquinone pool as a result of the MV-mediated cyclic flow.
日本植物生理学会の論文