Cytochrome C Oxidase Subunit Va （COX5A） is a member of the cytochrome c oxidase subunit 5A family. COX （Cytochrome C Oxidase）， which is the terminal component of the mitochondrial respiratory chain， catalyzes the electron transfer from reduced Cytochrome C to oxygen. The COX component is a heteromeric complex comprised of three catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits serve in electron transfer， and the nuclear-encoded subunits act in the regulation and assembly of the complex. COX5A is the heme A-containing chain of Cytochrome C Oxidase，which is the terminal oxidase in mitochondrial electron transport.
