Novel oxylipins formed from docosahexaenoic acid by potato lipoxygenase-10(S)-hydroxydocosahexaenoic acid and 10,20- dihydroxydocosahexaenoic acid

Igor A. Butovich, Mats Hamberg, Olof Rådmark

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Potato tuber lipoxygenase (ptLOX) has been shown to catalyze the aerobic formation of at least four major oxygenated derivatives of DHA. Two of the products-7,17(S)- and 10,17(S)-dihydro(pero)xy-DHA [7,17-and 10,17-diH(P)DHA]-were formed from soybean 15-LOX-derived 17(S)-hydro(pero)xy-DHA [17(S)-H(P)DHA], whereas two novel oxylipin compounds-10(S)-hydro(pero)xy-DHA and 10,20-dihydro(pero)xy-DHA [10(S)-H(P)DHA and 10,20-diH(P)DHA, respectively]-were the major direct products of DHA oxidation by ptLOX. The reactions proceeded relatively slowly but could be stimulated by catalytic amounts of SDS. Micromolar concentrations of 10(S)-HPDHA effectively abolished the kinetic lag period of ptLOX activation. Enzymatic activity with DHA or 17(S)-HPDHA as substrate was about 8% of that with linoleic acid-a standard natural ptLOX substrate-whereas 17(S)-HDHA was converted at a rate of ∼1%. The enzyme was relatively unstable and quickly inactivated during the reaction with DHA on with 17(S)-HPDHA (first-order kinetic constant of inactivation kin = 1.5 ± 0.3 min-1), but not with 17(S)-HDHA. Both 7,17- and 10,20-diH(P)DHA were clearly products of double oxygenation catalyzed by soybean 15-LOX and/or ptLOX. Our observation that ptLOX could convert 17-HDHA to 10,17-diH(P)DHA indicates that this dihydroxylated derivative of DHA also can be formed via a double lipoxygenation mechanism.

Original languageEnglish (US)
Pages (from-to)249-257
Number of pages9
JournalLipids
Volume40
Issue number3
DOIs
StatePublished - Mar 1 2005

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Cell Biology

Fingerprint Dive into the research topics of 'Novel oxylipins formed from docosahexaenoic acid by potato lipoxygenase-10(S)-hydroxydocosahexaenoic acid and 10,20- dihydroxydocosahexaenoic acid'. Together they form a unique fingerprint.

  • Cite this