人血浆中的胆固醇酯转运复合物。
A cholesteryl ester transfer complex in human plasma.
作者信息
Fielding P E, Fielding C J
出版信息
Proc Natl Acad Sci U S A. 1980 Jun;77(6):3327-30. doi: 10.1073/pnas.77.6.3327.
Immunoadsorption affinity chromatography has been used to define the structure of lipoproteins in human plasma containing lecithin:cholesterol acyltransferase (EC 2.3.1.43) (LCAT) and transfer protein (apo D). The whole of LCAT was absorbed by antibodies specific for apo D and for apo A-1, indicating that the enzyme is present in plasma exclusively as a complex with its cofactor (apo A-1) and product transfer protein (apo D). About 80% of apo D (but no LCAT) was removed by antibody to apo A-2, indicating the presence of most of apo D in the form of an enzyme-free complex will apo A-1 and apo A-2. After removal of LCAT with antibody to apo D, plasma was unreactive as a substrate with isolated LCAT, but substrate activity was generated by ultracentrifugal flotation with either intact or adsorbed plasma. The apparent stoichiometry of the complex with LCAT (LCAT:apo A-1:apo D) was 1.0:0.9:1.8; that of the complex containing apo A-1, apo A-2, and apo D was 3.9:2.2:1.0.
免疫吸附亲和色谱法已被用于确定人血浆中含卵磷脂
胆固醇酰基转移酶（EC 2.3.1.43）（LCAT）和转运蛋白（载脂蛋白D）的脂蛋白结构。整个LCAT被针对载脂蛋白D和载脂蛋白A-1的特异性抗体吸收，这表明该酶在血浆中仅以与其辅因子（载脂蛋白A-1）和产物转运蛋白（载脂蛋白D）的复合物形式存在。约80%的载脂蛋白D（但没有LCAT）被抗载脂蛋白A-2抗体去除，这表明大部分载脂蛋白D以与载脂蛋白A-1和载脂蛋白A-2形成的无酶复合物形式存在。用抗载脂蛋白D抗体去除LCAT后，血浆作为分离出的LCAT的底物无反应性，但通过超速离心浮选完整或吸附的血浆可产生底物活性。与LCAT的复合物（LCAT：载脂蛋白A-1：载脂蛋白D）的表观化学计量比为1.0：0.9：1.8；含有载脂蛋白A-1、载脂蛋白A-2和载脂蛋白D的复合物的表观化学计量比为3.9：2.2：1.0。
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