Formation of 12-[18-O]oxo-cis-10, cis-15-phytodienoic acid from 13[18-O]hydroperoxylinolenic acid by hydroperoxide cyclase.
13-[18-O]Hydroperoxylinolenic acid was permitted to react with an extract of flaxseed acetone powder containing hydroperoxide cyclase activity. The resulting product, 12-oxo-cis-10,cis-15-phytodienoic acid (12-oxo-PDA), contained 18O in the carbonyl oxygen at carbon 12, suggesting that an epoxide was an intermediate in the hyderoperoxide cyclase reaction. A substrate specificity study showed that a cis double bond beta, gamma to the conjugated hydroperoxide group was essential for the substrate to be converted to a cyclic product by hydroperoxide cyclase.
D002247:Carbon Isotopes; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D008042:Linolenic Acids / Q000378:metabolism*; D008054:Lipid Peroxides; D013058:Mass Spectrometry; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012639:Seeds / Q000201:enzymology
D002247:Carbon Isotopes; D005231:Fatty Acids, Unsaturated; D008042:Linolenic Acids; D008054:Lipid Peroxides; C025998:13-hydroperoxylinolenic acid; C025999:12-oxophytodienoic acid; D011451:Prostaglandin-Endoperoxide Synthases