Kinetics of oxidative phosphorylation in Paracoccus denitrificans. 2. Evidence for a kinetic and thermodynamic modulation of F0F1-ATPase by the activity of the respiratory chain.
(1) The affinity of the F0F1-ATPase from Paracoccus denitrificans for ATP during NADH-driven oxidative phosphorylation has been analyzed under different conditions by examining the type and extent of product inhibition. (2) A limited collapse of the protonmotive force (delta p) due to partial uncoupling does not increase the affinity for ATP at the active site(s) of the enzyme; instead, a partial noncompetitive inhibition becomes apparent, compatible with the binding of ATP to a noncatalytic site (or sites) with high affinity. (3) In contrast, partial inhibition of the electron-transport chain increases the extent of pure competitive product inhibition and, therefore, the affinity for ATP at the active site(s). (4) The results are interpreted as indicative of a modulation of the rate of ATP release from the active site(s) of the F0F1-ATPase which is controlled by the activity of the electron-transport chain and not by delta p.
Pérez
J A
JA
Department of Biochemistry, University of Oxford, U.K.
Ferguson
S J
SJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000935:Antifungal Agents / Q000494:pharmacology; D001665:Binding Sites; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D007700:Kinetics; D008433:Mathematics; D008689:Methacrylates; D008962:Models, Theoretical; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D010231:Paracoccus denitrificans / Q000201:enzymology / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology; D013816:Thermodynamics; D013844:Thiazoles / Q000494:pharmacology
D000935:Antifungal Agents; D003486:Cyanides; D008689:Methacrylates; D013844:Thiazoles; D012402:Rotenone; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; C030517:myxothiazol; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases