Zawadzki Z, Milne R W, Marcel Y L
Laboratory of Lipoprotein Metabolism, Clinical Research Institute, Montreal, Canada.
J Lipid Res. 1989 Jun;30(6):885-91.
Using monoclonal antibodies against apolipoprotein B (apoB) we studied changes in apoB immunoreactivity during copper ion-mediated oxidation of human low density lipoprotein (LDL). The radioimmunoassay experiments demonstrated the decrease of immunoreactivity of three different epitopes of apoB located in different parts of the protein; at the same time the immunoreactivity of another epitope, previously mapped to the C-terminal 20 amino acids of apoB increased markedly during the first 6 h of LDL oxidation and diminished gradually upon prolonged incubation with copper ions. The fate of LDL during oxidation was also monitored using electrophoretic techniques combined with immunodetection. These experiments showed a rapid fragmentation and disappearance of immunoreactive apoB. They also indicated that the diminishing LDL immunoreactivity detectable during oxidation is associated with apoB fragments still attached to the lipid core. The changes in apoB immunoreactivity during Cu2+ treatment of LDL are similar to those observed upon LDL aging. Therefore, it appears that the enhancement of immunoreactivity of the C-terminus of apoB is a general phenomenon associated with various kinds of oxidative modifications of LDL.
我们使用抗载脂蛋白B（apoB）的单克隆抗体，研究了在铜离子介导的人低密度脂蛋白（LDL）氧化过程中apoB免疫反应性的变化。放射免疫分析实验表明，位于蛋白质不同部位的apoB的三个不同表位的免疫反应性降低；与此同时，另一个先前定位在apoB C末端20个氨基酸的表位的免疫反应性在LDL氧化的最初6小时内显著增加，并在与铜离子长时间孵育后逐渐减弱。还使用电泳技术结合免疫检测监测了氧化过程中LDL的命运。这些实验显示出具有免疫反应性的apoB迅速断裂并消失。它们还表明，氧化过程中可检测到的LDL免疫反应性降低与仍附着在脂质核心上的apoB片段有关。在Cu2+处理LDL期间，apoB免疫反应性的变化与LDL老化时观察到的变化相似。因此，似乎apoB C末端免疫反应性的增强是与LDL各种氧化修饰相关的普遍现象。
