ubiquinone-8 has been researched along with ubiquinol* in 1 studies
1 other study(ies) available for ubiquinone-8 and ubiquinol
Article | Year |
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Role of a bound ubiquinone on reactions of the Escherichia coli cytochrome bo with ubiquinol and dioxygen.
To probe the functional role of a bound ubiquinone-8 in cytochrome bo-type ubiquinol oxidase from Escherichia coli, we examined reactions with ubiquinol-1 and dioxygen. Stopped-flow studies showed that anaerobic reduction of the wild-type and the bound ubiquinone-free (delta UbiA) enzymes with ubiquinol-1 immediately takes place with four kinetic phases. Replacement of the bound ubiquinone with 2,6-dibromo-4-cyanophenol (PC32) suppressed the anaerobic reduction of the hemes with ubiquinol-1 by eliminating the fast phase. Flow-flash studies in the reaction of the fully reduced enzyme with dioxygen showed that the heme b to heme o electron transfer occurs with a rate constant of approximately 10(4) s-1 in all three preparations. These results support our previous proposal that the bound ubiquinone is involved in facile oxidation of substrates in subunit II and subsequent intramolecular electron transfer to low-spin heme b in subunit I. Topics: Catalysis; Cytochrome b Group; Cytochromes; Escherichia coli; Escherichia coli Proteins; Heme; Oxidation-Reduction; Oxidoreductases; Oxygen; Spectrum Analysis, Raman; Time Factors; Ubiquinone | 1999 |