NADPH-dependent Enzymatic Peroxidation of Methyl-γ-linolenate

Abstract

The partially purified NADPH-cytochrome c reductase from rat liver microsomes catalyzed the peroxidation of methyl-γ-linolenate in the presence of ferric ions, EDTA and NADPH. Peroxidation of methyl-γ-linolenate and the generation of superoxide anions in the peroxidation system were suggested from the following observations:
(1) The concentration of TBA reactants and the optical density at 234 nm of chloroform extracts in the assay mixtures increased proportionally with the incubation time. These elevations were completely inhibited by the addition of BHT or α-tocopherol.
(2) The system catalyzed nitroblue tetrazolium reduction. This reaction did not occur in the absence of NADPH-cytochrome c reductase, NADPH or Tween 20.
Among enzymatic peroxidation products from methyl-γ-linolenate, oxygenated products which contained oxygen atom at C-6 or C-13 position were identified from these hydrogenated trimethylsilyl derivatives using gas chromatography and mass spectrometry.