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Kinetics of the electrogenic step and cytochrome b 6 and f redox changes in chloroplasts
Author(s) -
Selak M.A.,
Whitmarsh J.
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)80753-9
Subject(s) - cytochrome b6f complex , chemistry , electron transport chain , redox , cytochrome , cytochrome f , p700 , cytochrome c , cytochrome c1 , kinetics , cytochrome b , photochemistry , coenzyme q – cytochrome c reductase , stereochemistry , photosystem i , inorganic chemistry , biochemistry , photosynthesis , mitochondrion , photosystem ii , enzyme , physics , quantum mechanics , mitochondrial dna , gene
The spectroscopic measurements of the slow phase of the electrochromic effect and the redox kinetics of cytochrome b 6 and f provide strong evidence that a Q cycle operates in chloroplasts under conditions of non‐cyclic electron transport. The effect of HQNO and DBMIB on the extent and kinetics of these light‐induced changes places several constraints on the mechanism of quinol oxidation by the cyt. b/f —FeS complex: for each electron removed from the cyt. b/f —FeS complex by P700 an additional charge is transferred across the membrane; the cyclic pathway of electrons involved in quinol oxidation by the cyt. b/f —FeS complex includes at least one of the two b 6 cytochromes; the electrogenic step associated with quinol oxidation is subsequent to the reduction of at least one cytochrome b 6 quinol oxidation may proceed in a stepwise manner, with the first electron going to cytochrome b 6 and the second electron going to the FeS center and cytochrome f .