Activation of human plasma cholesteryl ester transfer protein by human apolipoprotein A-IV
Activation of human plasma cholesteryl ester transfer protein by human apolipoprotein A-IV
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DOI：
10.1016/0005-2760(95)00228-6
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发表时间：
1996-03-29
期刊：
影响因子：
--
通讯作者：
Yokoyama, S
中科院分区：
文献类型：
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作者：
Main, LA;Ohnishi, T;Yokoyama, S
本文研究了载脂蛋白（apo）A-IV在胆固醇酯转移蛋白（CETP; LTP）与低密度脂蛋白（LDL）直径的脂质微乳反应中的作用，并与apoA-I进行了比较。没有载脂蛋白CETP几乎不催化脂质转移。载脂蛋白A-IV结合到微乳液的表面平衡与其他螺旋载脂蛋白的类似的亲和力，并激活转移反应的胆固醇酯，三酰甘油和磷脂酰胆碱之间的乳液CETP。胆固醇酯和三酰甘油的转移反应的速率与结合到乳剂表面的apoA-IV的量成正比。对于磷脂酰胆碱，激活效果较差，直到40%的脂肪乳剂总结合容量被载脂蛋白占据。胆固醇酯是高度优选的CETP超过三酰甘油时，等量的这些脂质存在于核心的apoA-IV激活的乳液，导致几乎没有三酰甘油转移。而当乳液的核心仅为三酰甘油时，三酰甘油通过CETP的转移速率与胆固醇酯转移速率的顺序相同。这些发现都与apoA-I的结果相当，也与我们以前对其他两亲性螺旋载脂蛋白如apoA-II，E和C-III的观察结果一致。
Function of apolipoprotein (apo) A-IV was studied for its role in cholesteryl ester transfer protein (CETP; lipid transfer protein, LTP) reaction between lipid microemulsions having the diameter of low density lipoprotein, being compared to apoA-I. CETP hardly catalyzed lipid transfer without apolipoproteins. ApoA-IV bound to the surface of the microemulsion in equilibrium with a similar affinity to that of other helical apolipoproteins, and activated the transfer reaction by CETP of cholesteryl ester, triacylglycerol and phosphatidylcholine between the emulsions. The rate of the transfer reaction of cholesteryl ester and triacylglycerol was directly proportional to the amount of the bound apoA-IV to the surface of the emulsion. For phosphatidylcholine, activation was less effective until 40% of total binding capacity of lipid emulsion was occupied by the apolipoprotein. Cholesteryl ester was highly preferred by CETP over triacylglycerol when equal amount of these lipids was present in the core of the apoA-IV-activated emulsion, resulting in almost no triacylglycerol transfer. However, when the emulsion has the core exclusively of triacylglycerol, triacylglycerol was transferred by CETP with the rate in the same order as that of cholesteryl ester transfer. These findings were all comparable to the results with apoA-I, and also consistent with our previous observation for other amphiphilic helical apolipoproteins such as apoA-II, E and C-III.