Complex IV (CIV) is a copper-heme oxidase that couples electron transfer from cytochrome c to oxygen with proton extrusion across the inner membrane to contribute to the proton gradient required for ATP generation. This entry includes fungal mitochondrial complex IV assembly factor Cox20 []and its homologues (also known as (FAM36A) in metazoa [].Human CIV is formed by three catalytic core subunits (COX1/2/3). COX20 has been found to form a complex with SCO1, SCO2, and newly synthesized COX2. It may act as a chaperone in the early steps of COX2 maturation [].
