title: Occurrence of 9- and 13-keto-octadecadienoic acid in biological membranes oxygenated by the reticulocyte lipoxygenase.
abstract: Membranes of intact rabbit reticulocytes and rat liver mitochondrial membranes oxygenated by the pure reticulocyte lipoxygenase contain 13-keto-9Z,11E-octadecadienoic acid and 9-keto-10E,12Z-octadecadienoic acid. In mitochondrial membranes not treated with lipoxygenase and in rabbit erythrocyte membranes these products were not detected. The chemical structure of the compounds has been identified by cochromatography with authentic standards on various types of HPLC columns, by uv and ir spectroscopy and GC/MS. In the membranes of rabbit reticulocytes up to 2% of the linoleate residues are present as its 9- and 13-keto derivatives. Most of the keto compounds (up to 90%) are esterified in the membrane ester lipids, only about 10% were found in the free fatty acid fraction. It is proposed that the keto dienoic fatty acids are formed via decomposition of hydroperoxy polyenoic fatty acids originating from the oxygenation of the membrane lipids by the reticulocyte lipoxygenase.
authors.affiliation: Institute of Biochemistry, School of Medicine (Charité), Humboldt University, Berlin, German Democratic Republic.
authors.forename: H
authors.initials: H
authors.lastname: Kühn
authors.forename: J
authors.initials: J
authors.lastname: Belkner
authors.forename: R
authors.initials: R
authors.lastname: Wiesner
authors.forename: L
authors.initials: L
authors.lastname: Alder
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D007425:Intracellular Membranes / Q000201:enzymology; D007651:Keto Acids / Q000378:metabolism*; D008042:Linolenic Acids / Q000378:metabolism*; D008084:Lipoxygenase / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D008930:Mitochondria, Liver / Q000201:enzymology*; D011817:Rabbits; D051381:Rats; D012156:Reticulocytes / Q000201:enzymology*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005231:Fatty Acids, Unsaturated; D007651:Keto Acids; D008042:Linolenic Acids; D008563:Membrane Lipids; C064441:13-oxo-9,11-octadecadienoic acid; C062143:9-oxo-10,12-octadecadienoic acid; D008084:Lipoxygenase