KAURENOLIDE BIOSYNTHESIS IN A CELL-FREE SYSTEM FROM CUCURBITA MAXIMA SEEDS

Article abstract of DOI:10.1016/0031-9422(81)83019-1

A new product obtained by incubation of <2-14C>-mevalonic acid with a cell-free system from Cucurbita maxima endosperm was identified by GC-MS as ent-kaura-6,16-dien-19-oic acid.When this compound was reincubated with the microsomal fraction it was converted to 7β-hydroxykaurenolide and hence to 7β,12α-dihydroxykaurenolide.The dienoic acid was also obtained by incubation of ent-kaurene, ent-kaurenol, ent-kaurenal and ent-kaurenoic acid, but not ent-7α-hydroxykaurenoic acid, with the microsomal fraction.Thus, in the C. maxima cell-free system, the kaurenolides are formed by a pathway which branches from the GA pathway at ent-kaurenoic acid and proceeds via the dienoic acid.Key Word Index- Cucurbita maxima; Cucurbitaceae; biosynthesis; cell-free system; kaurenolides; gibberellins; ent-kaura-6,16-dien-19-oic acid.