- BIOSYNTHESIS OF GIBBERELLIN A12-ALDEHYDE, GIBBERELLIN A12 AND THEIR KAURENOID PRECURSORS FROM MEVALONIC ACID IN A CELL-FREE SYSTEM FROM IMMATURE SEED OF PHASEOLUS COCCINEUS
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A cell-free system capable of gibberellin (GA) biosynthesis has been prepared from immature seed of Phaseolus coccineus.This system converted mevalonic acid (MVA) to ent-kaurene, ent-kaurenoic acid, ent-kauradienoic acid, ent-7α-hydroxykaurenoic acid, ent-6α,7α-dihydroxykaurenoic acid, GA12-aldehyde and GA12. ent-Kaurene was converted to ent-kaurenol, ent-kaurenal, ent-kaurenoic acid and ent-7α-hydroxykaurenoic acid.All identifications were by GC/MC.The pathway from MVA to GA12-aldehyde in this species thus appears to be the same as that found in cell-free preparations derived from immature seed of other species.Key Word Index-Phaseolus coccineus; Leguminosae; runner bean; seed development; biosynthesis; cell-free system; HPLC; GC/MC; gibberellin.
- Turnbull, Colin G. N.,Crozier, Alan,Schwenen, Ludger,Graebe, Jan E.
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- KAURENOLIDE BIOSYNTHESIS IN A CELL-FREE SYSTEM FROM CUCURBITA MAXIMA SEEDS
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A new product obtained by incubation of -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.
- Hedden, Peter,Graebe, Jan E.
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p. 1011 - 1016
(2007/10/02)
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