Extent of copper LDL oxidation depends on oxidation time and copper/LDL ratio: chemical characterization.
The aim of our study was to determine, as a function of [Cu(2+)]/[LDL] ratios (0.5 and 0.05) and of oxidation phases, the extent of LDL oxidation by assessing the lipid and apo B oxidation products. The main results showed that: (i) kinetics of conjugated diene formation presented four phases for Cu(2+)/LDL ratio of 0.5 and two phases for [Cu(2+)]/[LDL] ratio of 0.05; (ii) oxidation product formation (cholesteryl ester and phosphatidylcholine hydroperoxides, apo B carbonyl groups) occurred early in the presence of endogenous antioxidants, under both copper oxidation conditions; (iii) apo B carbonylated fragments appeared when antioxidants were totally consumed at [Cu(2+)]/[LDL] ratio of 0.5; and (iv) antioxidant concentrations were stable, oxysterol formation was negligible, and no carbonylated fragment was detected at [Cu(2+)]/[LDL] ratio of 0.05. Depending on the copper/LDL ratio, oxidized LDL differ greatly in the nature of lipid peroxidation product and the degree of apo B fragmentation.
Zarev
Stéphanie
S
Laboratoire de Biochimie Métabolique et Clinique, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75270 Paris Cedex 06, France. ptherond@ch-versailles.fr
Bonnefont-Rousselot
Dominique
D
Jedidi
Iness
I
Cosson
Claudine
C
Couturier
Martine
M
Legrand
Alain
A
Beaudeux
Jean-Louis
JL
Thérond
Patrice
P
D001055:Apolipoproteins B / Q000138:chemical synthesis / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D003300:Copper / Q000737:chemistry*; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008077:Lipoproteins, LDL / Q000737:chemistry*; D010084:Oxidation-Reduction; D024502:alpha-Tocopherol / Q000737:chemistry*; D019207:beta Carotene / Q000737:chemistry*
D001055:Apolipoproteins B; D008055:Lipids; D008077:Lipoproteins, LDL; D019207:beta Carotene; D003300:Copper; D024502:alpha-Tocopherol