Reaction: (1a) ent-kaur-16-en-19-oate + NADPH + H+ + O2 = ent-7α-hydroxykaur-16-en-19-oate + NADP+ + H2O
(1b) ent-7α-hydroxykaur-16-en-19-oate + NADPH + H+ + O2 = gibberellin A12 aldehyde + NADP+ + 2 H2O
(1c) gibberellin A12 aldehyde + NADPH + O2 = gibberellin A12 + NADP+ + H2O
For diagram click here.
Systematic name: ent-kaur-16-en-19-oate,NADPH:oxygen oxidoreductase (hydroxylating)
Comments: Requires cytochrome P450. 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, CAS registry number: 337507-95-6
References:
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]