The intramitochondrial ATP/ADP-ratio controls cytochrome c oxidase activity allosterically.
Recently the signal transduction function for oxidative phosphorylation was found to be second order in ADP [Jeneson, J.A.L., Wiseman, R.W., Westerhoff, H.V. and Kushmerick, M.J. (1996) J. Biol. Chem. 271, 27995-279981, but the molecular mechanism of signal transduction remained unclear. Previously we described inhibition of cytochrome c oxidase by intramitochondrial ATP, accompanied by a change of hyperbolic into sigmoidal kinetics. The present study describes a sigmoidal relationship also between the ascorbate respiration of reconstituted cytochrome c oxidase and intraliposomal ADP concentration. Its possible role in the control of oxidative phosphorylation and cell respiration is discussed.
Arnold
S
S
Fachbereich Chemie, Philipps-Universität, Marburg, Germany.
Kadenbach
B
B
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000494:Allosteric Regulation; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D002417:Cattle; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007700:Kinetics; D008929:Mitochondria, Heart / Q000378:metabolism*