Contribution of copper binding to the inhibition of lipid oxidation by plasmalogen phospholipids.
The role of plasmalogen phospholipids for copper-induced lipid oxidation was evaluated. Using 1H-NMR we observed that the copper (CuSO4)-promoted oxidative degradation of polyunsaturated fatty acids in micellar solution was dose-dependently attenuated by the plasmalogen lysoplasmenylethanolamine from bovine brain (lysoBP-PtdEtn). This was due to a direct interaction of copper ions with the plasmalogen-specific enol ether double bond. The enol ether methine 1H signal decreased on the addition of copper, saturation being reached at a molar ratio of lysoBP-PtdEtn to copper of 1:1. The original 1H signal was recovered almost completely after the addition of EDTA. Enrichment of micelles and low-density lipoproteins (LDLs) with plasmalogen phospholipids led to a decrease in the Cu(II) concentration in the aqueous media. After loading of LDLs in vitro with BP-PtdEtn, the LDL-dependent formation of Cu(I) was decreased, in particular in particles experimentally supplemented with alpha-tocopherol. The suppression of copper-promoted lipid oxidation that was observed in the presence of plasmalogen phospholipids plus alpha-tocopherol was greater than the sum of the protective effects elicited by the two substances alone. In conclusion, the formation of a complex between copper ions and the plasmalogens accounts partly for their inhibition of copper-induced lipid oxidation.
Hahnel
D
D
Physiologisches Institut der Universität München, Pettenkoferstrasse 12, D-80336 München, Germany.
Huber
T
T
Kurze
V
V
Beyer
K
K
Engelmann
B
B
D003300:Copper / Q000378:metabolism*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008823:Micelles; D010084:Oxidation-Reduction; D010955:Plasmalogens / Q000378:metabolism*; D011485:Protein Binding
D008077:Lipoproteins, LDL; D008823:Micelles; D010955:Plasmalogens; D003300:Copper