title: Detection of two further beta-type cytochromes in Rhodopseudomonas spheroides.
abstract: The photosynthetically-incompetent mutant V-2 of Rhodopseudomonas spheroides which is incapable of synthesising bacteriochlorophyll was grown aerobically under conditions of both high and low aeration. Potentiometric titration a at 560 nm minus 570 nm revealed the presence of several different components tentatively identified as b-type cytochromes. Two such components of oxidation-reduction midpoint potentials of +390 mV +/- 10 mV and +255 mV +/- 7mV have not previously been detected in membranes of Rps. spheroides. These components have also been resolved by difference spectra at controlled oxidation-reduction potentials and fourth derivative spectra. Neither component appeared to react with CO. With increasing aeration of the culture medium the relative concentration of these two b-type cytochromes diminished, whilst that of the a-type oxidase increased.
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002248:Carbon Monoxide / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism*; D004227:Dithionite / Q000494:pharmacology; D005292:Ferricyanides / Q000494:pharmacology; D010101:Oxygen Consumption; D011199:Potentiometry; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013696:Temperature; D013772:Tetramethylphenylenediamine / Q000494:pharmacology
chemical_list: D003580:Cytochromes; D005292:Ferricyanides; D004227:Dithionite; D002248:Carbon Monoxide; D013772:Tetramethylphenylenediamine; D001205:Ascorbic Acid