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Cu 2+ ‐induced low density lipoprotein peroxidation is dependent on the initial O 2 concentration: An O 2 consumption study
Author(s) -
Lodge John K.,
Traber Maret G.,
Sadler Peter J.
Publication year - 2000
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-000-0623-x
Subject(s) - chemistry , low density lipoprotein , lipid peroxidation , clinical chemistry , copper , lipidology , phase (matter) , lipoprotein , oxygen , lag , medicine , biochemistry , endocrinology , antioxidant , cholesterol , organic chemistry , biology , computer network , computer science
Atherosclerotic plaques form in the arterial intima, where low density lipoprotein (LDL) is thought to be oxidatively modified at sites which may contain catalytic amounts of copper in the presence of low O 2 tension. We have investigated O 2 consumption during LDL peroxidation induced by Cu 2+ ions in vitro and found two phases: a lag phase followed by a phase of rapid O 2 consumption. The length of the lag phase was dependent on Cu 2+ and on initial O 2 concentrations; increasing either decreased the lag time; however, LDL concentration had no effect. LDL‐induced Cu 2+ reduction, however, was not affected by low initial O 2 concentrations, suggesting that O 2 is not required for LDL‐mediated reduction of Cu 2+ . Following the lag phase O 2 consumption was dependent upon LDL or initial O 2 concentrations; Cu 2+ concentrations had little effect, suggesting that the propagation phase is more dependent on the presence of LDL lipids and O 2 as substrates for the reaction. In summary, LDL peroxidation takes place in the presence of Cu 2+ at low O 2 tension; however, the reaction is dependent upon initial O 2 concentrations; increases shorten the lag phase and accelerate O 2 consumption.