Reaction: β-amyrin + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = 11-oxo-β-amyrin + 2 [oxidized NADPH—hemoprotein reductase] + 3 H2O (overall reaction)
(1a) β-amyrin + [reduced NADPH—hemoprotein reductase] + O2 = 11α-hydroxy-β-amyrin + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) 11α-hydroxy-β-amyrin + [reduced NADPH—hemoprotein reductase] + O2 = 11-oxo-β-amyrin + [oxidized NADPH—hemoprotein reductase] + 2 H2O
For diagram of reaction click here.
Other name(s): CYP88D6
Systematic name: β-amyrin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (hydroxylating)
Comments: A cytochrome P-450 (heme-thiolate) protein from the plant Glycyrrhiza uralensis (Chinese licorice) that participates in the glycyrrhizin biosynthesis pathway. The enzyme is also able to oxidize 30-hydroxy-β-amyrin to 11α,30-dihydroxy-β-amyrin but this is not thought to be part of glycyrrhizin biosynthesis.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Seki, H., Ohyama, K., Sawai, S., Mizutani, M., Ohnishi, T., Sudo, H., Akashi, T., Aoki, T., Saito, K. and Muranaka, T. Licorice β-amyrin 11-oxidase, a cytochrome P450 with a key role in the biosynthesis of the triterpene sweetener glycyrrhizin. Proc. Natl. Acad. Sci. USA 105 (2008) 14204-14209. [PMID: 18779566]