Lipoxygenase pathway in tulip: biosynthesis of ketols

The metabolism in vitro of [1-C-14]linoleate, [1-C-14]linolenate and their 9(S)-hydroperoxides in tulip (Tulipa gesneriana) was found to be under the control of 9-lipoxygenase and allene oxide synthase, and directed towards a lpha -ketol, gamma -ketol and the novel compound (12Z)-10-oxo-11-hydroxy-12 -octadecadienoic acid (10,11-ketol). Potent activity of allene oxide cyclas e (in bulbs) and a new enzyme, gamma -ketol reductase (in bulbs and leaves) , was detected. Metabolism in flowers is directed predominantly towards alp ha -ketol hydroperoxide.