Patterns of change in cytochrome c oxidase redox status

Redox transitions between oxygen intermediates in cytochrome-c oxidase.

Some intermediates in the reduction of O2 to water by cytochrome-c oxidase have been characterized by optical, Raman, and magnetic circular dichroism spectroscopy. The so-called "peroxy" (P) and "ferryl" (F) forms of the enzyme, which have been considered to be intermediates of the oxygen reaction, can be generated when the oxidized enzyme reacts with H2O2, or when the two-electron reduced ("CO...

Redox-Controlled Proton Gating in Bovine Cytochrome c Oxidase

Cytochrome c oxidase is the terminal enzyme in the electron transfer chain of essentially all organisms that utilize oxygen to generate energy. It reduces oxygen to water and harnesses the energy to pump protons across the mitochondrial membrane in eukaryotes and the plasma membrane in prokaryotes. The mechanism by which proton pumping is coupled to the oxygen reduction reaction remains unresol...

Redox-linked Proton Transfer by Cytochrome c Oxidase

Mitochondrial regulation of caspase activation by cytochrome oxidase and tetramethylphenylenediamine via cytosolic cytochrome c redox state.

Cytochrome c release from mitochondria induces caspase activation in cytosols; however, it is unclear whether the redox state of cytosolic cytochrome c can regulate caspase activation. By using cytosol isolated from mammalian cells, we find that oxidation of cytochrome c by added cytochrome oxidase stimulates caspase activation, whereas reduction of cytochrome c by added tetramethylphenylenedia...

Cytochrome c oxidase.

Within the past year, the structures of the cytochrome c oxidase from the soil bacterium Paracoccus denitrificans and of the metal centers of the cytochrome c oxidase from bovine heart mitochondria, both determined at 2.8 A resolution by X-ray crystallography, have been reported. The structures form a basis for understanding the mechanism of this redox-coupled transmembrane proton pump, which i...