Prevention of in vitro low-density lipoprotein oxidation by an albumin-containing Lp A-I subfraction.
High-density lipoprotein (HDL) and two lipoprotein particles, those containing apo A-I and apo A-II (LpA-I:A-II) and those containing only apo A-I (LpA-I) were examined for their effect on Cu(2+)-catalyzed oxidation of human low-density lipoprotein (LDL). Lipoproteins and lipoprotein particles were prepared from plasma samples of five healthy subjects. LDL and HDL were purified by ultracentrifugation, LpA-I and LpA-I:A-II were isolated by an immunoaffinity chromatography procedure. The contaminating albumin often linked to the LpA-I affinity purified particles was eliminated by selected affinity immunosorption. The presence of HDL, LpA-I or LpA-I:A-II, at an apo A-I-containing lipoproteins/LDL ratio of 1, did not prevent LDL oxidation when assessed by oxidation kinetics, electrophoretic mobility, amounts of thiobarbituric acid-reactive products and fragmentation of apo B-100. On the other hand, when the albumin removing step was omitted, the subfraction of albumin-containing LpA-I particles impeded and even inhibited the oxidation of LDL in an albumin dose-dependent manner.
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INSERM U325, Institut Pasteur, Lille, France.
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Fruchart
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Fiévet
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D003300:Copper / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D017270:Lipoprotein(a) / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008075:Lipoproteins, HDL / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet
D017270:Lipoprotein(a); D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D012709:Serum Albumin; C078260:lipoprotein A-I; D003300:Copper