title: Characterization of the intermediates in the reaction of membrane-bound mixed-valence-state cytochrome oxidase with oxygen at low temperatures by optical spectroscopy in the visible region.
abstract: The 'pure' difference spectra of the three species, IM, IIM and IIIM, formed in the low-temperature reaction of membrane-bound mixed-valence-state cytochrome oxidase with O2 relative to unliganded membrane-bound mixed-valence-state cytochrome oxidase were characterized by optical spectroscopy in the visible region. The difference spectrum of species IM was characterized by a peak at 590 nm and a trough at 608 nm, that of species IIM by a peak at 606 nm, and that of species IIIM by a peak at 610 nm. A comparison with the difference spectra of species IIM and IIIM obtained with soluble cytochrome oxidase [Clore, Andréasson, Karlsson, Aasa & Malmström (1980) Biochem. J. 185, 155-167] revealed small but significant differences in the peak positions and bandwidths of the 605-610 nm absorption band.
mesh_terms: D000818:Animals; D002248:Carbon Monoxide; D002417:Cattle; D003080:Cold Temperature; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007425:Intracellular Membranes / Q000201:enzymology*; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D013053:Spectrophotometry / Q000379:methods
chemical_list: D002248:Carbon Monoxide; D003576:Electron Transport Complex IV; D010100:Oxygen