[Kinetics of NADH oxidation of NAD+ reduction by mitochondrial complex I].
The kinetics of the NAD: artificial acceptor-oxidoreductase and delta mu H(+)-dependent succinate: NAD(+)-oxidoreductase reactions (reverse electron transfer) reactions catalyzed by the membrane-bound complex I was studied. The values of apparent rate constants of dissociation of complexes of the oxidized and reduced enzyme with NAD+ and NADH were determined. It was shown that the apparent affinity of NADH for the oxidized complex I is by nearly three orders of magnitude as high as that of the reduced one; a reverse correlation is found for NAD+. A kinetic scheme of complex I functioning in the forward and reverse reactions, according to which the free reduced enzyme is not an intermediate of the forward (NADH-oxidase) reaction and the free oxidized enzyme is not an intermediate of the reverse (NAD(+)-reductase) reaction, is proposed.
Avraam
R
R
Kotliar
A B
AB
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002417:Cattle; D004579:Electron Transport; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*
D009243:NAD; D000255:Adenosine Triphosphate; D009247:NADH, NADPH Oxidoreductases
Kinetika okisleniia NADH i vosstanovleniia NAD+ mitokhondrial'nym kompleksom I.