IUBMB Enzyme Nomenclature


Accepted name: ent-kaurenoic acid monooxygenase

Reaction: ent-kaur-16-en-19-oate + 3 [reduced NADPH—hemoprotein reductase] + 3 O2 = gibberellin A12 + 3 [oxidized NADPH—hemoprotein reductase] + 4 H2O (overall reaction)
(1a) ent-kaur-16-en-19-oate + [reduced NADPH—hemoprotein reductase] + O2 = ent-7α-hydroxykaur-16-en-19-oate + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) ent-7α-hydroxykaur-16-en-19-oate + [reduced NADPH—hemoprotein reductase] + O2 = gibberellin A12 aldehyde + [oxidized NADPH—hemoprotein reductase] + 2 H2O
(1c) gibberellin A12 aldehyde + [reduced NADPH—hemoprotein reductase] + O2 = gibberellin A12 + [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

Other name(s): KAO1 (gene name); CYP88A3 (gene name); ent-kaurenoic acid oxidase

Systematic name: ent-kaur-16-en-19-oate,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (hydroxylating)

Comments: A cytochrome P-450 (heme-thiolate) protein from plants. Catalyses three sucessive oxidations of ent-kaurenoic acid. The second step includes a ring-B contraction giving the gibbane skeleton. In pumpkin (Cucurbita maxima) ent-6α,7α-dihydroxykaur-16-en-19-oate is also formed.

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


1. Helliwell, C.A., Chandler, P.M., Poole, A., Dennis, E.S. and Peacock, W.J. The CYP88A cytochrome P450, ent-kaurenoic acid oxidase, catalyzes three steps of the gibberellin biosynthesis pathway. Proc. Natl. Acad. Sci. USA 98 (2001) 2065-2070. [PMID: 11172076]

[EC created 2002 as EC, transferred 2018 to EC]

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