Radical initiated alpha-tocopherol depletion and lipid peroxidation in mitochondrial membranes.
The relationships between antioxidant status, lipid peroxidation and membrane protein integrity have been studied in an isolated mitochondrial membrane system. Tocopherol was shown to be present in both the outer and inner membrane of normal rat liver mitochondria; 77.3 and 22.3% of the total alpha-tocopherol was present in the outer and inner membranes, respectively. The endogenous alpha-tocopherol was depleted in a time-dependent manner by low levels of ferrous iron and by irradiation in the presence or absence of ferrous iron. This antioxidant depletion was followed by the appearance of lipid hydroperoxides. Fragmentation of monoamine oxidase, an integral outer membrane protein, was observed at irradiation doses that caused by antioxidant depletion and peroxide generation.
Thomas
S M
SM
Department of Biochemistry and Biology, Brunel University, Uxbridge, U.K.
Gebicki
J M
JM
Dean
R T
RT
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005296:Ferrous Compounds / Q000494:pharmacology; D005609:Free Radicals; D006878:Hydroxides / Q000494:pharmacology; D017665:Hydroxyl Radical; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure*; D008995:Monoamine Oxidase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013367:Submitochondrial Particles / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D014810:Vitamin E / Q000378:metabolism*
D005296:Ferrous Compounds; D005609:Free Radicals; D006878:Hydroxides; D008054:Lipid Peroxides; D014810:Vitamin E; D017665:Hydroxyl Radical; D008995:Monoamine Oxidase