Nicholson, Donald W. and Neupert, Walter
Import of cytochrome c into mitochondria. Reduction of heme, mediated by NADH and flavin nucleotides, is obligatory for its covalent linkage to apocytochrome c.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 86, No. 12: pp. 4340-4344
The covalent attachment of heme to apocytochrome c, and therefore the import of cytochrome c into mitochondria, is dependent on both NADH plus a cytosolic cofactor that has been identified to be FMN or FAD. NADH in concert with flavin nucleotides mediates the reduction of heme. Heme in the reduced state is a prerequisite for its covalent attachment to apocytochrome c by the enzyme cytochrome c heme lyase and thus for subsequent translocation of cytochrome c across the outer mitochondrial membrane during import.