Reaction: germacra-1(10),4,11(13)-trien-12-oate + NADPH + H+ + O2 = (+)-costunolide + NADP+ + 2 H2O
For diagram of reaction click here.
Systematic name: germacra-1(10),4,11(13)-trien-12-oate,NADPH:oxygen oxidoreductase (6α-hydroxylating)
Comments: A heme-thiolate protein (P-450). The enzyme hydroxylates carbon C-6 of germacra-1(10),4,11(13)-trien-12-oate to give 6α-hydroxygermacra-1(10),4,11(13)-trien-12-oate, which probably spontaneously cyclises to form the lactone ring.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
1. de Kraker, J.W., Franssen, M.C., Joerink, M., de Groot, A. and Bouwmeester, H.J. Biosynthesis of costunolide, dihydrocostunolide, and leucodin. Demonstration of cytochrome p450-catalyzed formation of the lactone ring present in sesquiterpene lactones of chicory. Plant Physiol. 129 (2002) 257-268. [PMID: 12011356]