title: Measurement of the redox state of the ubiquinone pool in Rhodobacter capsulatus membrane fragments.
abstract: The dependence of the respiratory rate on the redox poise of the quinone pool was investigated in wild type and mutant membranes of Rhodobacter capsulatus. A linear relationship has been found between these two parameters only when succinate was oxidized by the bc1 complex. Conversely, a marked nonlinear relationship was observed between the Q-pool reduction level and the respiratory rate when O2 uptake occurred via the alternative oxidase. In addition, it was found that this latter pathway was not engaged until Q-pool reduction level reached approximately 25%. These results are discussed within the framework of a homogeneous pool regulating both photosynthetic and respiratory fluxes.
authors.affiliation: Department of Biology, University of Bologna, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Zannoni
authors.forename: A L
authors.initials: AL
authors.lastname: Moore
mesh_terms: D003575:Cytochromes c1 / Q000378:metabolism; D004579:Electron Transport; D009154:Mutation; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D016354:Rhodobacter capsulatus / Q000201:enzymology* / Q000235:genetics; D014451:Ubiquinone / Q000378:metabolism*
chemical_list: D014451:Ubiquinone; D003575:Cytochromes c1; C025204:Ubiquinone Q2