摘要
本文用Cu^(2+)引发低密度脂蛋白(LDL)的脂质过氧化反应,探讨了脂质过氧化修饰对LDL结构及组成的影响。在无EDTA的情况下,LDL(1mg/ml)与Cu2^(2+)(10umol/L)37℃温育:2hLDL原有的黄色消失,8h有不溶物质产生。硫代巴比妥酸(TBARS)在短期内有大幅度上升,80％以上呈游离状态。维生素正在2h内下降60％,6h下降88％。游离氨基减少,琼脂糖电泳迁移加快,二者呈负相关(r=-0.99)。荧光物质含量则随温育时间的延长而增加。在修饰程度较低时,apoB以降解为主,修饰程度升高时,降解的apoB又可重新聚合成为大分子。与Cu^(2+)(脂质过氧化)修饰相比,用丙二醛(MDA)(10mmol/L)直接修饰的LDL,仅游离氨基减少,电泳迁移加快。
It is considered that oxidative modification of LDL is one of the causes that induce foam cell formation in atherosclerotic plaque. The oxidative modification involves lipid peroxidation mediated by oxygen free radical. We used Cu2+ as a proxidant initiating lipid peroxidation and elucidated the effect of oxidative modification on the structure and constituents of LDL by determination of the contents of TBA reactive substances (TBARS) , vitamin E, cholesterol, lipofusion, free amino groups in LDL and its agarose gel electrophoretic mobility. Under EDTA free condition, LDL ( 1 mg/ml ) was incubated with Cu2+ (10μ mol/L) at 37℃. The yellow colour of LDL faded in two hours and insoluble material appeared in 8 hours. TBARS increased quickly in a short period and most of the TBARS produced were free from LDL. Vatimin E decreased by 60% in 2 hours and 80 %in 6 hours. Cholesterol also decreased with the prolongation of incubation time. The level of free amino groups in LDL decreased and its electrophoretic mobility in agarose gel enhanced. There was a negative relationship between them (r-0.99). Lipofusion also increased with the prolongation of incubation time. SDS-poly acry-lamide gel electrophoresis ( SDS-PAGE ) showed that apo B was not only frag-emented but also aggregated. Compared with Cu2+ ( lipid peroxidative ) modification, LDL modified directly by MDA ( 10mmol/L ) could only decrease the content of free amino groups and enhance electrophoretic mobility, but without the other changes as occured in case of Cu2+ modified LDL.
出处
《第一军医大学学报》
CSCD
1991年第4期287-291,共5页
Journal of First Military Medical University
基金
国家自然科学基金资助项目
关键词
低密度脂蛋白
丙二醛
维生素E
LDL
oxidative modification
malondialdehyde modification lipid peroxidation
vitamin E
Lipofusion
