Kinetics of ubisemiquinone redox changes in primary reactions of bacterial photosynthesis
Verkhovskiĭ, M.I.; Kaurov, B.S.; Rubin, A.B.; Shinkarev, V.P.
Molekuliarnaia Biologiia 15(3): 589-600
1981
ISSN/ISBN: 0026-8984 PMID: 6789145 Document Number: 172925
Absorbance changes at 450 nm of the semiquinone form of the secondary electron acceptor were studied in chromatophores of Rhodospirillum rubrum. When chromatophores are illuminated by a series of single turnover flashes ubisemiquinone is formed and destroyed on alternate flashes at ambient redox potential from 100 to 250 mV. A simple kinetic model of the binary oscillations is suggested. On the base of the model it is shown that the rate constant of electron transfer from primary to secondary quinone after the first flash is larger that after the second flash. Cooperativity in electron transfer from primary to secondary quinone can be explained by electrostatic interactions of charged carriers.