Degradation of linoleic acid hydroperoxides by a cysteine . FeCl3 catalyst as a model for similar biochemical reactions. II. Specificity in formation of fatty acid epoxides.
1. The degradation of linoleic acid hydroperoxide by cysteine and FeCl3 resulted in formation of a number of oxygenated fatty acids, among which isomeric epoxyoxooctadecenoic and epoxyhydroxyoctadecenoic acids were major products. Pure isomeric hydroperoxides, either 13-L(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid or 9-D(S)-hydroperoxy-trans-10,cis-12-octadecadienoic acid, were transformed into either 12,13-epoxides or 9,10-epoxides, respectively. 2. From 13-L(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid, the epoxides were identified as trans-12,13-epoxy-9-oxo-trans-10-octadecenoic acid, trans-12,13-epoxy-9-hydroxy-trans-10-octadecenoic acid, cis-12,13-epoxy-9-oxo-trans-10-octadecenoic acid, trans-12,13-epoxy-erythro-11-hydroxy-cis(trans)-9-octadecenoic acid and trans-12,13-epoxy-threo-11-hydroxy-cis(trans)-9-octadecenoic acid. 3. The 12,13-epoxides were found to be optically active, indicating that the chiral center of the 13-L(S)-hydroperoxy carbon was retained. 4. Although many epoxy fatty acids previously have been identified as linoleic acid hydroperoxide products, this study reports a more complete structural analysis of the various epoxides and allows an assessment of the mechanisms of their formation from hydroperoxides.
D002384:Catalysis; D002712:Chlorides; D003545:Cysteine / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D004988:Ethers, Cyclic / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005290:Ferric Compounds / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D007501:Iron / Q000378:metabolism*; D007536:Isomerism; D008041:Linoleic Acids / Q000378:metabolism*; D008054:Lipid Peroxides / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy
D002712:Chlorides; D004852:Epoxy Compounds; D004988:Ethers, Cyclic; D005227:Fatty Acids; D005290:Ferric Compounds; D008041:Linoleic Acids; D008054:Lipid Peroxides; C008285:linoleic acid hydroperoxide; D007501:Iron; D003545:Cysteine; C024555:ferric chloride