Lodge J K, Traber M G, Sadler P J
Department of Chemistry, Birkbeck College, University of London, United Kingdom.
Lipids. 2000 Oct;35(10):1087-92. doi: 10.1007/s11745-000-0623-x.
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 O2 tension. We have investigated O2 consumption during LDL peroxidation induced by Cu2+ ions in vitro and found two phases: a lag phase followed by a phase of rapid O2 consumption. The length of the lag phase was dependent on Cu2+ and on initial O2 concentrations; increasing either decreased the lag time; however, LDL. concentration had no effect. LDL-induced Cu2+ reduction, however, was not affected by low initial O2 concentrations, suggesting that O2 is not required for LDL-mediated reduction of Cu2+. Following the lag phase, O2 consumption was dependent upon LDL or initial O2 concentrations; Cu2+ concentrations had little effect, suggesting that the propagation phase is more dependent on the presence of LDL lipids and O2 as substrates for the reaction. In summary, LDL peroxidation takes place in the presence of Cu2+ at low O2 tension; however, the reaction is dependent upon initial O2 concentrations; increases shorten the lag phase and accelerate O2 consumption.
动脉粥样硬化斑块形成于动脉内膜，在低氧张力条件下，低密度脂蛋白（LDL）被认为在可能含有催化量铜的部位发生氧化修饰。我们研究了体外Cu2+离子诱导LDL过氧化过程中的氧气消耗情况，发现有两个阶段：一个延迟期，随后是快速氧气消耗阶段。延迟期的长度取决于Cu2+和初始氧气浓度；增加其中任何一个都会缩短延迟时间；然而，LDL浓度没有影响。然而，LDL诱导的Cu2+还原不受低初始氧气浓度的影响，这表明LDL介导的Cu2+还原不需要氧气。在延迟期之后，氧气消耗取决于LDL或初始氧气浓度；Cu2+浓度影响很小，这表明增殖阶段更依赖于LDL脂质和氧气作为反应底物的存在。总之，LDL过氧化在低氧张力下Cu2+存在时发生；然而，反应取决于初始氧气浓度；增加氧气浓度会缩短延迟期并加速氧气消耗。
