Regulation of the H+/e- stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios.
This paper describes the effect of intramitochondrial ATP/ADP ratios on the H+/e- stoichiometry of reconstituted cytochrome c oxidase (COX) from bovine heart. At 100% intraliposomal ATP the H+/e- stoichiometry of the reconstituted enzyme is decreased to half of the value measured below 98% intraliposomal ATP (above 2% ADP), while it remains constant up to 100% ADP. The decrease is obtained with different COX preparations, independent of the absolute value of the H+/e- stoichiometry. Decrease of H+/e- stoichiometry is prevented by preincubation of the enzyme with a tissue-specific monoclonal antibody to subunit VIa-H (heart type). Tissue-specific regulation of the efficiency of energy transduction in COX of muscle mitochondria could have a physiological function in maintaining the body temperature at rest or sleep, i.e. at low ATP expenditure.
Frank
V
V
Fachbereich Chemie, Philipps-Universität, Marburg, Germany.
Kadenbach
B
B
D000244:Adenosine Diphosphate / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002417:Cattle; D003574:Cytochrome c Group / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004583:Electrons; D017136:Ion Transport; D008081:Liposomes / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism; D010084:Oxidation-Reduction; D011510:Proteolipids / Q000378:metabolism; D011522:Protons; D014475:Uncoupling Agents / Q000494:pharmacology
D003574:Cytochrome c Group; D008081:Liposomes; D011510:Proteolipids; D011522:Protons; D014475:Uncoupling Agents; C020485:proteoliposomes; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D003576:Electron Transport Complex IV