IUBMB Enzyme Nomenclature


Accepted name: trans-cinnamate 4-monooxygenase

Reaction: trans-cinnamate + [reduced NADPH—hemoprotein reductase] + O2 = 4-hydroxycinnamate + [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

Other name(s): cinnamic acid 4-hydroxylase; CA4H; cytochrome P450 cinnamate 4-hydroxylase; cinnamate 4-hydroxylase; cinnamate 4-monooxygenase; cinnamate hydroxylase; cinnamic 4-hydroxylase; cinnamic acid 4-monooxygenase; cinnamic acid p-hydroxylase; t-cinnamic acid hydroxylase; trans-cinnamate 4-hydroxylase; trans-cinnamic acid 4-hydroxylase; CYP73A1 (gene name)

Systematic name: trans-cinnamate,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (4-hydroxylating)

Comments: A cytochrome P-450 (heme-thiolate) protein found in plants. The enzyme is involved in flavonoid biosynthesis.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Potts, J.R.M., Weklych, R. and Conn, E.E. The 4-hydroxylation of cinnamic acid by sorghum microsomes and the requirement for cytochrome P-450. J. Biol. Chem. 249 (1974) 5019-5026. [PMID: 4153152]

2. Russell, D.W. and Conn, E.E. The cinnamic acid 4-hydroxylase of pea seedlings. Arch. Biochem. Biophys. 122 (1967) 256-268. [PMID: 4383827]

3. Pierrel, M.A., Batard, Y., Kazmaier, M., Mignotte-Vieux, C., Durst, F. and Werck-Reichhart, D. Catalytic properties of the plant cytochrome P450 CYP73 expressed in yeast. Substrate specificity of a cinnamate hydroxylase. Eur. J. Biochem. 224 (1994) 835-844. [PMID: 7925408]

[EC created 1976 as EC, transferred 2018 to EC]

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