Lipoxygenase pathway in tulip: biosynthesis of ketols.
The metabolism in vitro of [1-(14)C]linoleate, [1-(14)C]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 alpha-ketol, gamma-ketol and the novel compound (12Z)-10-oxo-11-hydroxy-12-octadecadienoic acid (10,11-ketol). Potent activity of allene oxide cyclase (in bulbs) and a new enzyme, gamma-ketol reductase (in bulbs and leaves), was detected. Metabolism in flowers is directed predominantly towards alpha-ketol hydroperoxide.
Grechkin
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AN
Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan, 420503, Russia. grechkin@sci.kcn.ru
Mukhtarova
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LS
Hamberg
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D002250:Carbon Radioisotopes; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D019668:Liliaceae / Q000201:enzymology*; D019787:Linoleic Acid / Q000378:metabolism*; D008054:Lipid Peroxides / Q000378:metabolism*; D008084:Lipoxygenase / Q000378:metabolism*; D010840:Phytosterols / Q000096:biosynthesis*; D018515:Plant Leaves / Q000201:enzymology; D018517:Plant Roots / Q000201:enzymology; D018547:Plant Stems / Q000201:enzymology; D017962:alpha-Linolenic Acid / Q000378:metabolism*
D002250:Carbon Radioisotopes; D008054:Lipid Peroxides; D010840:Phytosterols; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid; D008084:Lipoxygenase; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase