The action of defined oxygen-centred free radicals on human low-density lipoprotein.
The effects of defined oxygen-centred free radicals on human low-density lipoprotein (LDL) structure and receptor affinity are discussed in relation to the mechanisms of cell-mediated oxidative modification of LDL. Both hydroxyl (OH.) and hydroperoxyl (HO2.) radicals caused depletion of endogenous alpha-tocopherol and formation of hydroperoxides. Superoxide (O2-.) radicals produced only very limited oxidation, but could potentiate oxidation stimulated by the addition of Cu2+. All these radicals enhanced the net negative charge of intact LDL and induced fragmentation of apolipoprotein B-100 (apo B). OH. also caused cross-linking of apo B. Radical attack decreased the affinity of LDL for the fibroblast apo B/E receptor, but did not enhance its endocytosis by mouse macrophages.
Bedwell
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Department of Biology and Biochemistry, Brunel University, Uxbridge, Middlesex, U.K.
Dean
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RT
Jessup
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W
D001055:Apolipoproteins B / Q000378:metabolism; D001665:Binding Sites; D003300:Copper; D004587:Electrophoresis, Agar Gel; D005609:Free Radicals; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000378:metabolism*; D010100:Oxygen; D013481:Superoxides / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism
D001055:Apolipoproteins B; D005609:Free Radicals; D008077:Lipoproteins, LDL; D013481:Superoxides; D014810:Vitamin E; D003300:Copper; D010100:Oxygen