title: Double hydroperoxidation of alpha-linolenic acid by potato tuber lipoxygenase.
abstract: The potato tuber lipoxygenase preparations convert alpha-linolenic acid not only to 9(S)-HPOTE, but also to some more polar metabolites. Two of these polar products, I and II, with ultraviolet absorbance maxima at 267 nm were purified by HPLC. It was found that metabolites I and II have, respectively, one and two hydroperoxy groups. Products of NaBH4 reduction of both I and II were identified by their chemical ionization and electron impact mass spectra and by 1H-NMR spectra as 9,16-dihydroxy-10(E), 12(Z), 14(E)-octadecatrienoic acid. The obtained results suggest that compound II is 9.16-dihydroperoxy-10(E), 12(Z), 14(E)-octadecatrienoic acid and product I is a mixture of two positional isomers, 9-hydroxy-16-hydroperoxy-10(E),12(Z),14(E)-octadecatrienoic and 9-hydroperoxy-16-hydroxy-10(E),12(Z),14(E)-octadecatrienoic acids. Lipoxygenase converts efficiently [14C]9-HOTE into product I. Also, both metabolites I and II are the products of double dioxygenation. The second oxygenation at C-16 position as well as the first one at C-9 is controlled by lipoxygenase.
authors.affiliation: Institute of Biology, USSR Academy of Sciences, Kazan.
authors.forename: A N
authors.initials: AN
authors.lastname: Grechkin
authors.forename: R A
authors.initials: RA
authors.lastname: Kuramshin
authors.forename: E Y
authors.initials: EY
authors.lastname: Safonova
authors.forename: Y J
authors.initials: YJ
authors.lastname: Yefremov
authors.forename: S K
authors.initials: SK
authors.lastname: Latypov
authors.forename: A V
authors.initials: AV
authors.lastname: Ilyasov
authors.forename: I A
authors.initials: IA
authors.lastname: Tarchevsky
mesh_terms: D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D008042:Linolenic Acids / Q000378:metabolism*; D015227:Lipid Peroxidation; D008084:Lipoxygenase / Q000378:metabolism*; D013058:Mass Spectrometry; D011865:Radioisotope Dilution Technique; D011198:Solanum tuberosum / Q000201:enzymology*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002250:Carbon Radioisotopes; D008042:Linolenic Acids; D008084:Lipoxygenase