title: The formation of threo-11-hydroxy-trans-12: 13-epoxy-9-cis-octadecenoic acid by enzymic isomerisation of 13-L-hydroperoxy-9-cis, 11-transoctadecadienoic acid by soybean lipoxygenase-1.
abstract: The interaction of soybean lipoxygenase-1 with 13-L-hydroperoxy-9-cis, 11-trans-octadecadienoic acid (13-hydroperoxy-linoleate), the product of the enzymic dioxygenation of linoleic acid,  yields either a yellow or a purple-coloured enzyme species depending on the amount of product used. With an excess of 13-hydroperoxy-linoleate a labile purple-coloured enzyme species is formed which reverts to a yellow-coloured form with concomitant conversion of the hydroperoxy compound. In this reaction 13-hydroperoxy-linoleate isomerises into threo-11-hydroxy-trans-12:13 epoxy-9-cis-octadecenoic acid as could be concluded from nuclear magnetic resonance and mass spectral data. Experiments with 13-[18O2]hydroperoxy-linoleate showed a high retention (70%) of the 2 hydroperoxy oxygen atoms in the end product.
mesh_terms: D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D006880:Hydroxy Acids / Q000096:biosynthesis*; D008084:Lipoxygenase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008968:Molecular Conformation; D010944:Plants / Q000201:enzymology*; D013025:Glycine max; D013237:Stereoisomerism
chemical_list: D005231:Fatty Acids, Unsaturated; D006880:Hydroxy Acids; D008084:Lipoxygenase