IUBMB Enzyme Nomenclature


Accepted name: β-amyrin 28-monooxygenase

Reaction: β-amyrin + 3 O2 + 3 [reduced NADPH—hemoprotein reductase] = oleanolate + 3 [oxidized NADPH—hemoprotein reductase] + 4 H2O (overall reaction)
(1a) β-amyrin + O2 + [reduced NADPH—hemoprotein reductase] = erythrodiol + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) erythrodiol + O2 + [reduced NADPH—hemoprotein reductase] = oleanolic aldehyde + [oxidized NADPH—hemoprotein reductase] + 2 H2O
(1c) oleanolic aldehyde + O2 + [reduced NADPH—hemoprotein reductase] = oleanolate + [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

Other name(s): CYP716A52v2; CYP716A12; CYP16A75; β-amyrin 28-oxidase

Systematic name: β-amyrin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (28-hydroxylating)

Comments: A cytochrome P-450 (heme-thiolate) protein found in plants. The enzyme is involved in the biosynthesis of oleanane-type triterpenoids, such as ginsenoside Ro. The enzyme from Medicago truncatula (barrel medic) (CYP716A12) can also convert α-amyrin and lupeol to ursolic acid and betulinic acid, respectively. The enzyme from Maesa lanceolata (false assegai) (CYP16A75) does not catalyse the reaction to completion, resulting in accumulation of both intermediates.

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


1. Fukushima, E.O., Seki, H., Ohyama, K., Ono, E., Umemoto, N., Mizutani, M., Saito, K. and Muranaka, T. CYP716A subfamily members are multifunctional oxidases in triterpenoid biosynthesis. Plant Cell Physiol 52 (2011) 2050-2061. [PMID: 22039103]

2. Han, J.Y., Kim, M.J., Ban, Y.W., Hwang, H.S. and Choi, Y.E. The involvement of β-amyrin 28-oxidase (CYP716A52v2) in oleanane-type ginsenoside biosynthesis in Panax ginseng. Plant Cell Physiol 54 (2013) 2034-2046. [PMID: 24092881]

3. Moses, T., Pollier, J., Faizal, A., Apers, S., Pieters, L., Thevelein, J.M., Geelen, D. and Goossens, A. Unraveling the triterpenoid saponin biosynthesis of the African shrub Maesa lanceolata. Mol. Plant 8 (2015) 122-135. [PMID: 25578277]

[EC created 2015 as EC, transferred 2018 to EC]

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