IUBMB Enzyme Nomenclature


Accepted name: cytochrome-c oxidase

Reaction: 4 ferrocytochrome c + O2 + 4 H+= 4 ferricytochrome c + 2 H2O

Other name(s): cytochrome oxidase; cytochrome a3; cytochrome aa3; Warburg's respiratory enzyme; indophenol oxidase; indophenolase; complex IV (mitochondrial electron transport); ferrocytochrome c oxidase; NADH cytochrome c oxidase

Systematic name: ferrocytochrome-c:oxygen oxidoreductase

Comments: A cytochrome of the a type containing copper. The reduction of O2 to water is accompanied by the extrusion of four protons from the intramitochondrial compartment. Several bacteria appear to contain analogous oxidases.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9001-16-5


1. Keilin, D. and Hartree, E.F. Cytochrome oxidase. Proc. R. Soc. Lond. B Biol. Sci. 125 (1938) 171-186.

2. Keilin, D. and Hartree, E.F. Cytochrome and cytochrome oxidase. Proc. R. Soc. Lond. B Biol. Sci. 127 (1939) 167-191.

3. Wainio, W.W., Eichel, B. and Gould, A. Ion and pH optimum for the oxidation of ferrocytochrome c by cytochrome c oxidase in air. J. Biol. Chem. 235 (1960) 1521-1525.

4. Yonetani, T. Studies on cytochrome oxidase. II. Steady state properties.J. Biol. Chem. 235 (1960) 3138-3243.

5. Yonetani, T.Studies on cytochrome oxidase. III. Improved purification and some properties. J. Biol. Chem. 236 (1961) 1680-1688.

[EC created 1961, modified 2000]

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