Inhibition of the phosphate-stimulated cytochrome c oxidase activity by thiophosphate.
Yeast and mammalian cytochrome c oxidase activity is inhibited by thiophosphate. This inhibition was observed when using either whole mitochondria or the isolated or reconstituted enzyme. The kinetics of the reduction reaction enabled us to demonstrate that thiophosphate acted on the electron transfer between hemes a and a3. With whole mitochondria, phosphate alone stimulated respiration. The inhibition induced by thiophosphate was suppressed by phosphate only in mitochondria, but not when the isolated enzyme was used. The possibility of a kinetic regulation is discussed.
Manon
S
S
Institut de Biochimie Cellulaire et de Neurochimie du Centre National de la Recherche Scientifique, Bordeaux, France.
Camougrand
N
N
Guerin
M
M
D000818:Animals; D004579:Electron Transport / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007700:Kinetics; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D010101:Oxygen Consumption / Q000187:drug effects; D010710:Phosphates / Q000494:pharmacology* / Q000502:physiology*; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology
D010710:Phosphates; D003576:Electron Transport Complex IV; C035638:thiophosphoric acid