[Kinetics of NADH oxidation of NAD+ reduction by mitochondrial complex I].
Biokhimiia (Moscow, Russia)
confidence
Key findings
Kinetic study of NADH oxidation and NAD+ reduction by mitochondrial complex I; no clinical or biological endpoints reported.
View source on PubMed (PMID 1747428) ↗
- Population
- In vitro mitochondrial complex I (not human)
- Blinding
- not_reported
- Controls
- none
- Drug class
- coenzyme
Full abstract
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.