Abstract
The form of cytochrome o that predominates in Vitreoscilla cells having various levels of respiratory activity was studied by using untreated, frozen-thawed, and starved cells, which had respiratory rates decreasing in the order given. Direct spectral observation revealed that the oxygenated form of cytochrome o predominated during the aerobic steady-state oxidation of endogenous substrate or exogenous glutamate in untreated and frozen-thawed cells and was replaced by the reduced form when the cell suspensions became anaerobic. The respiratory rates, estimated inversely from the time of duration of the steady state, were correlated to the rates of oxygen consumption for the various cells. Oxidized cytochrome o predominated in aerobic starved cells. These results indicate the involvement of three forms of cytochrome o--oxidized, reduced, and oxygenated--in the catalytic and cyclic change of this cytochrome. The oxygenated form also appeared after the addition of hydrogen peroxide to the cells, but only the oxidized form appeared when ethyl hydrogen peroxide was added. The appearance of the oxygenated form with the addition of hydrogen peroxide was probably due to the reaction of the reduced cytochrome with the oxygen that had evolved by the action of catalase present in the cells.
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Selected References
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- Liu C. Y., Webster D. A. Spectral characteristics and interconversions of the reduced oxidized, and oxygenated forms of purified cytochrome o. J Biol Chem. 1974 Jul 10;249(13):4261–4266. [PubMed] [Google Scholar]
- Webster D. A., Hackett D. P. Respiratory chain of colorless algae. II. Cyanophyta. Plant Physiol. 1966 Apr;41(4):599–605. doi: 10.1104/pp.41.4.599. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Webster D. A., Liu C. Y. Reduced nicotinamide adenine dinucleotide cytochrome o reductase associated with cytochrome o purified from Vitreoscilla. Evidence for an intermediate oxygenated form of cytochrome o. J Biol Chem. 1974 Jul 10;249(13):4257–4260. [PubMed] [Google Scholar]
- Webster D. A., Orii Y. Oxygenated Cytochrome o. An active intermediate observed in whole cells of Vitreoscilla. J Biol Chem. 1977 Mar 25;252(6):1834–1836. [PubMed] [Google Scholar]
- Webster D. A. The formation of hydrogen peroxide during the oxidation of reduced nicotinamide adenine dinucleotide by cytochrome o from Vitreoscilla. J Biol Chem. 1975 Jul 10;250(13):4955–4958. [PubMed] [Google Scholar]