NADH Dehydrogenase Ubiquinone 1 Alpha Subcomplex 9 (NDUFa9)

NDUFa9 belongs to the complex I NDUFA9 subunit family. The multisubunit NADH:ubiquinone oxidoreductase (complex I) is the first enzyme complex in the electron transport chain of mitochondria. . Fearnley et al. (1991) isolated the genes encoding the 39- and 42-kD subunits of bovine complex I. Both proteins are part of the hydrophobic protein fraction of the enzyme. However, both are predominantly hydrophilic, and appear to lie mostly outside the lipid bilayer. In a heterogeneous nuclear cDNA library of human chromosome 12p transcribed sequences, Baens et al. (1993) identified CC6, a cDNA encoding the human homolog of the bovine 39-kD protein. The bovine and human 39-kD subunits are 78% identical on the amino acid level.