Ubiquinol:Cytochrome c Oxidoreductase (Complex III)

EVIDENCE FOR STOICHEIOMETRIC ASSOCIATION By C. IAN RAGAN* and CHRISTINE HERON

1. The NADH-ubiquinone oxidoreductase complex (Complex I) and the ubiquinolcytochrome c oxidoreductase complex (Complex III) combine in a 1: 1 molar ratio to give NADH-cytochrome c oxidoreductase (Complex I-Complex III). 2. Experiments C a the inhibition ofthe NADH-cytochrome c oxidoreductase activity of mixtures ofComplexes I and III by rotenone and antimycin indicate that electron transfer be...

Ubiquinol:cytochrome c oxidoreductase (complex III). Effect of inhibitors on cytochrome b reduction in submitochondrial particles and the role of ubiquinone in complex III.

Two sets of studies have been reported on the electron transfer pathway of complex III in bovine heart submitochondrial particles (SMP). 1) In the presence of myxothiazol, MOA-stilbene, stigmatellin, or of antimycin added to SMP pretreated with ascorbate and KCN to reduce the high potential components (iron-sulfur protein (ISP) and cytochrome c(1)) of complex III, addition of succinate reduced ...

Energy converting NADH:quinone oxidoreductase (complex I).

NADH:quinone oxidoreductase (complex I) pumps protons across the inner membrane of mitochondria or the plasma membrane of many bacteria. Human complex I is involved in numerous pathological conditions and degenerative processes. With 14 central and up to 32 accessory subunits, complex I is among the largest membrane-bound protein assemblies. The peripheral arm of the L-shaped molecule contains ...

Purification of a three-subunit ubiquinol-cytochrome c oxidoreductase complex from Paracoccus denitrificans.

A ubiquinol-cytochrome c oxidoreductase (cytochrome bc1) complex has been purified from the plasma membrane of aerobically grown Paracoccus denitrificans by extraction with dodecyl maltoside and ion exchange chromatography of the extract. The purified complex contains two spectrally and thermodynamically distinct b cytochromes, cytochrome c1, and a Rieske-type iron-sulfur protein. Optical spect...

Topographical distribution of redox centres and the Qo site in ubiquinol-cytochrome-c oxidoreductase (complex III) and ligand structure of the Rieske iron-sulphur cluster.