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Measurement of the redox state of the ubiquinone pool in Rhodobacter capsulatus membrane fragments
Author(s) -
Zani Davide,
Moore Anthony L.
Publication year - 1990
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(90)80387-x
Subject(s) - rhodobacter , redox , rhodospirillaceae , quinone , chemistry , mutant , photosynthetic reaction centre , photosynthesis , membrane , rhodobacter sphaeroides , biophysics , homogeneous , biochemistry , photochemistry , biology , inorganic chemistry , physics , gene , thermodynamics
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 bc 1 complex. Conversely, a marked nonlinear relationship was observed between the Q‐pool reduction level and the respiratory rate when O 2 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.