title: Redox Bohr effects and the role of heme a in the proton pump of bovine heart cytochrome c oxidase.
abstract: Structural and functional observations are reviewed which provide evidence for a central role of redox Bohr effect linked to the low-spin heme a in the proton pump of bovine heart cytochrome c oxidase. Data on the membrane sidedness of Bohr protons linked to anaerobic oxido-reduction of the individual metal centers in the liposome reconstituted oxidase are analysed. Redox Bohr protons coupled to anaerobic oxido-reduction of heme a (and Cu(A)) and Cu(B) exhibit membrane vectoriality, i.e. protons are taken up from the inner space upon reduction of these centers and released in the outer space upon their oxidation. Redox Bohr protons coupled to anaerobic oxido-reduction of heme a(3) do not, on the contrary, exhibit vectorial nature: protons are exchanged only with the outer space. A model of the proton pump of the oxidase, in which redox Bohr protons linked to the low-spin heme a play a central role, is described. This article is part of a Special Issue entitled: Allosteric cooperativity in respiratory proteins.
authors.affiliation: Department of Medical Biochemistry, University of Bari, Bari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Capitanio
authors.forename: Pietro Luca
authors.initials: PL
authors.lastname: Martino
authors.forename: Nazzareno
authors.initials: N
authors.lastname: Capitanio
authors.forename: Sergio
authors.initials: S
authors.lastname: Papa
mesh_terms: D000818:Animals; D002417:Cattle; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D006418:Heme / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology; D010084:Oxidation-Reduction; D017494:Proton Pumps / Q000737:chemistry / Q000378:metabolism; D011522:Protons
chemical_list: D017494:Proton Pumps; D011522:Protons; D006418:Heme; D003300:Copper; D003576:Electron Transport Complex IV