title: Spectral and kinetic equivalence of oxidized cytochrome C oxidase as isolated and "activated" by reoxidation.
abstract: The spectral and kinetic characteristics of two oxidized states of bovine heart cytochrome c oxidase (CcO) have been compared. The first is the oxidized state of enzyme isolated in the fast form (O) and the second is the form that is obtained immediately after oxidation of fully reduced CcO with O2 (OH). No observable differences were found between O and OH states in: (i) the rate of anaerobic reduction of heme a3 for both the detergent-solubilized enzyme and for enzyme embedded in its natural membraneous environment, (ii) the one-electron distribution between heme a3 and CuB in the course of the full anaerobic reduction, (iii) the optical and (iv) EPR spectra. Within experimental error of these characteristics both forms are identical. Based on these observations it is concluded that the reduction potentials and the ligation states of heme a3 and CuB are the same for CcO in the O and OH states.
authors.affiliation: Department of Biophysics, Safarik University, Jesenna 5, 04154 Kosice, Slovak Republic.
authors.forename: Daniel
authors.initials: D
authors.lastname: Jancura
authors.forename: Vladimir
authors.initials: V
authors.lastname: Berka
authors.forename: Marian
authors.initials: M
authors.lastname: Antalik
authors.forename: Jaroslava
authors.initials: J
authors.lastname: Bagelova
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gennis
authors.forename: Graham
authors.initials: G
authors.lastname: Palmer
authors.forename: Marian
authors.initials: M
authors.lastname: Fabian
mesh_terms: D000818:Animals; D002417:Cattle; D003300:Copper / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism; D004583:Electrons; D006418:Heme / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006418:Heme; D003300:Copper; D003576:Electron Transport Complex IV; D010100:Oxygen