Members of this family mediate the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone, the reaction that occurs being: NADH + ubiquinone = NAD(+) + ubiquinol [1][2].

1: Adaptive selection of mitochondrial complex I subunits during primate radiation. Mishmar D, Ruiz-Pesini E, Mondragon-Palomino M, Procaccio V, Gaut B, Wallace DC; Gene. 2006;378:11-18. PMID:16828987

2: Identification and primary structure of five human NADH-ubiquinone oxidoreductase subunits. Ton C, Hwang DM, Dempsey AA, Liew CC; Biochem Biophys Res Commun 1997;241:589-594. PMID:9425316