title: Rat testis mitochondrial phospholipid hydroperoxide glutathione peroxidase does not protect endogenous vitamin E against Fe2+-induced (lipo)peroxidation.
abstract: Rat testis mitochondria contain large amounts of both seleno-enzyme phospholipid hydroperoxide glutathione peroxidase (EC 1.11.1.12, PHGPx) and alpha-tocopherol. The scavenger role of vitamin E consists of transforming the lipoperoxyl radicals into lipid hydroperoxides, thus interrupting the peroxidative cascade. These hydroperoxides are in turn substrates of the PHGPx, which is considered one of the most important specific enzymes capable of protecting, in situ, the membranes from lipid peroxidation. A connection or synergism could, therefore, be envisaged between vitamin and enzyme opposing lipid damage in the mitochondria. Here we present data concerning the HPLC evaluation of vitamin E consumption in rat testis mitochondria and mitochondrial membranes, under different conditions of PHGPx activity, after Fe2+-induced lipid peroxidation. We have found that the enzyme activity, under the conditions tested, does not spare vitamin E from its peroxidation, therefore indicating that the postulated synergism between PHGPx and alpha-tocopherol can be excluded in rat testis mitochondria.
authors.affiliation: Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Godeas
authors.forename: F
authors.initials: F
authors.lastname: Tramer
authors.forename: G
authors.initials: G
authors.lastname: Sandri
authors.forename: E
authors.initials: E
authors.lastname: Panfili
mesh_terms: D000367:Age Factors; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007501:Iron / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D008623:Mercaptoethanol / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000378:metabolism* / Q000648:ultrastructure; D014810:Vitamin E / Q000378:metabolism*
chemical_list: D007461:Iodoacetates; D008563:Membrane Lipids; D010743:Phospholipids; D014810:Vitamin E; D008623:Mercaptoethanol; D007501:Iron; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase; D005978:Glutathione; D019807:Iodoacetic Acid