Physiological role of oxygenated cytochrome o: observations on whole-cell suspensions of Vitreoscilla.
AUTOR(ES)
Webster, D A
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=224767Documentos Relacionados
- Inhibition of methanogenesis in salt marsh sediments and whole-cell suspensions of methanogenic bacteria by nitrogen oxides.
- Use of extracts versus whole-cell bacterial suspensions in the identification of Staphylococcus aureus beta-lactamase variants.
- Microbial Oxidation of Hydrocarbons and Related Compounds by Whole-Cell Suspensions of the Methane-Oxidizing Bacterium H-2
- Simple filter paper procedure for estimation of glucose uptake via group translocation by whole-cell suspensions of bacteria.
- Stretch effects on whole-cell currents of guinea-pig urinary bladder myocytes.