This protein is one of the nuclear-coded polypeptide chains of cytochrome c oxidase, the terminal oxidase in mitochondrial electron transport. Expressed in testis. Not expressed in brain, heart, liver, kidney, spleen, lung, duodenum, muscle, epididymis, vagina, uterus and ovary. On the 2D-gel the determined pI of this protein is: 6.0, its MW is: 14.7 kDa. Belongs to the cytochrome c oxidase 5b family.