Cytochrome c oxidase, subunit VIa (IPR001349)

Short name: Cyt_c_oxidase_su6a

Overlapping homologous superfamilies

Family relationships



Cytochrome c oxidase (EC: is an oligomeric enzymatic complex which is a component of the respiratory chain complex and is involved in the transfer of electrons from cytochrome c to oxygen [PMID: 6307356]. In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane.

In eukaryotes, in addition to the three large subunits, I, II and III, that form the catalytic centre of the enzyme complex, there are a variable number of small polypeptidic subunits. One of these subunits is known as VIa in vertebrates and fungi. Mammals have two tissue-specific isoforms of VIa, a liver (VIa-L) and a heart and skeletal muscle isoform (VIa-H). Mammalian VIa-H induces a slip in CcO (decrease in proton/electron stoichiometry) at high intramitochondrial ATP/ADP ratios, while VIa-L induces a permanent slip in CcO, depending on the presence of cardiolipin and palmitate [PMID: 12909344]. Only one form is found in fish [PMID: 9107314].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0004129 cytochrome-c oxidase activity

Cellular Component

GO:0005743 mitochondrial inner membrane
GO:0005751 mitochondrial respiratory chain complex IV

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.