Cytochrome c oxidase

Cytochrome c oxidase
The crystal structure of bovine cytochrome c oxidase in a phospholipid bilayer. The intermembrane space lies to top of the image. Adapted from PDB: 1OCC​ (It is a homodimer in this structure)
Identifiers
EC no.	1.9.3.1
CAS no.	9001-16-5
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Cytochrome c oxidase
Subunit I and II of Complex IV excluding all other subunits, PDB: 2EIK​
Identifiers
Symbol	Cytochrome c oxidase
OPM superfamily	4
OPM protein	2dyr
Membranome	257

The enzyme cytochrome c oxidase or Complex IV (was EC 1.9.3.1, now reclassified as a translocase EC 7.1.1.9) is a large transmembrane protein complex found in bacteria, archaea, and the mitochondria of eukaryotes.^[1]

It is the last enzyme in the respiratory electron transport chain of cells located in the membrane. It receives an electron from each of four cytochrome c molecules and transfers them to one oxygen molecule and four protons, producing two molecules of water. In addition to binding the four protons from the inner aqueous phase, it transports another four protons across the membrane, increasing the transmembrane difference of proton electrochemical potential, which the ATP synthase then uses to synthesize ATP.