Time-resolved resonance Raman study of dioxygen reduction by cytochrome c oxidase

Direct detection of a dioxygen adduct of cytochrome a3 in the mixed valence cytochrome oxidase/dioxygen reaction.

Time-resolved resonance Raman spectra have been recorded during the reaction of mixed valence (a3+ a2+(3)) cytochrome oxidase with dioxygen at room temperature. In the spectrum recorded at 10 microseconds subsequent to carbon monoxide photolysis, a mode is observed at 572 cm-1 that shifts to 548 cm-1 when the experiment is repeated with 18O2. The appearance of this mode is dependent upon the la...

Time-resolved optical absorption studies of cytochrome oxidase dynamics.

Time-resolved spectroscopic studies in our laboratory of bovine heart cytochrome c oxidase dynamics are summarized. Intramolecular electron transfer was investigated upon photolysis of CO from the mixed-valence enzyme, by pulse radiolysis, and upon light-induced electron injection into the cytochrome c/cytochrome oxidase complex from a novel photoactivatable dye. The reduction of dioxygen to wa...

Time-Resolved Resonance Raman Study on Oxygen Activation by Cytochrome c Oxidase in Intact Whole Mitochondria

Prokaryotic models for mitochondrial cytochrome c oxidase.

992 Introduction Cytochrome c oxidase is a fascinating enzyme that has attracted the attention of numerous researchers over the past two decades [ 1-61. The enzyme catalyses the one-electron oxidation of cytochrome c and the four-electron reduction of molecular oxygen to water. In doing so, the enzyme electrogenically pumps protons across the inner mitochondrial membrane, thus generating a tran...

Near-infrared time-resolved optical absorption studies of the reaction of fully reduced cytochrome c oxidase with dioxygen.

Electron transfer during the reaction of fully reduced bovine heart cytochrome oxidase with dioxygen has been studied at 24 degrees C in the near-infrared region following photolysis of the fully reduced CO-bound complex. The transient spectral changes and kinetics were followed on microsecond to millisecond time scales at nine different wavelengths between 597 and 935 nm and were analyzed usin...