title: Ubiquinone reduction and proton uptake by chromatophores of Rhodopseudomonas sphaeroides R-26: periodicity of two in consecutive light flashes.
abstract: Chromatophores of Rhodopseudomonas sphaeroides strain R-26 were subjected to a series of brief flashes of light in the presence of diaminodurene as an electron donor. Odd-numbered flashes induced the reduction of ubiquinone to the anionic semiquinone, as indicated by absorbance changes near 450 nm. This reaction was not attended by proton binding. Even-numbered flashes caused disappearance of the semiquinone, presumably by conversion to the fully reduced form. This reaction was attended by proton uptake.
mesh_terms: D020130:Bacterial Chromatophores / Q000378:metabolism*; D066298:In Vitro Techniques; D008027:Light; D010084:Oxidation-Reduction; D010777:Photochemistry; D011522:Protons; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013053:Spectrophotometry; D014451:Ubiquinone / Q000378:metabolism*
chemical_list: D011522:Protons; D014451:Ubiquinone