Nitroreductase activity of NADH dehydrogenase of the respiratory redox chain

Abstract

An NADH-dependent nitroreductase from the inner membrane of ox liver mitochondria copurified with Complex I of the respiratory redox chain (NADH: ubiquinone oxidoreductase, EC 1.6.5.3). The corresponding nitroreductase from ox heart mitochondria co-purified with the NADH-cytochrome c reductase of Mahler, Sarkar & Vernon ([1952] J. Biol. Chem. 199, 585-597] (NADH: (acceptor) oxidoreductase, EC 1.6.99.3], a component of Complex I that contains the FMN. The mitochondrial nitroreductase activity is attributed to the flavoprotein component of Complex I.