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
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IntEnzIntEnz view
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MetaCycmetabolic pathway
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NCBIproteins
Cytochrome c oxidase
Subunit I and II of Complex IV excluding all other subunits, PDB: 2EIK
Identifiers
SymbolCytochrome c oxidase
OPM superfamily4
OPM protein2dyr
Membranome257

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.

  1. ^ Castresana J, Lübben M, Saraste M, Higgins DG (June 1994). "Evolution of cytochrome oxidase, an enzyme older than atmospheric oxygen". The EMBO Journal. 13 (11): 2516–2525. doi:10.1002/j.1460-2075.1994.tb06541.x. PMC 395125. PMID 8013452.