Dashti N, Koren E, Alaupovic P
Lipoprotein and Atherosclerosis Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104.
Biochem Biophys Res Commun. 1989 Aug 30;163(1):574-80. doi: 10.1016/0006-291x(89)92176-1.
The purpose of this study was to identify the apolipoprotein A-containing lipoprotein particles produced by HepG2 cells. The apolipoprotein A-containing lipoproteins separated from apolipoprotein B-containing lipoproteins by affinity chromatography of culture medium on concanavalin A were fractionated on an immunosorber with monoclonal antibodies to apolipoprotein A-II. The retained fraction contained apolipoproteins A-I, A-II and E, while the unretained fraction contained apolipoproteins A-I and E. Both fractions were characterized by free cholesterol as the major and triglycerides and cholesterol esters as the minor neutral lipids. Further chromatography of both fractions on an immunosorber with monoclonal antibodies to apolipoprotein A-I showed that 1) apolipoprotein A-II only occurs in association with apolipoprotein A-I, 2) apolipoprotein A-IV is only present as part of a separate lipoprotein family (lipoprotein A-IV), and 3) apolipoprotein E-enriched lipoprotein A-I:A-II and lipoprotein A-I are the main apolipoprotein A-containing lipoproteins secreted by HepG2 cells.
本研究的目的是鉴定HepG2细胞产生的含载脂蛋白A的脂蛋白颗粒。通过伴刀豆球蛋白A对培养基进行亲和层析，将含载脂蛋白A的脂蛋白与含载脂蛋白B的脂蛋白分离，然后在含有抗载脂蛋白A-II单克隆抗体的免疫吸附剂上进行分级分离。保留级分含有载脂蛋白A-I、A-II和E，而未保留级分含有载脂蛋白A-I和E。两个级分均以游离胆固醇作为主要中性脂质，甘油三酯和胆固醇酯作为次要中性脂质为特征。用抗载脂蛋白A-I单克隆抗体对两个级分进一步进行免疫吸附层析，结果表明：1）载脂蛋白A-II仅与载脂蛋白A-I结合存在；2）载脂蛋白A-IV仅作为一个单独的脂蛋白家族（脂蛋白A-IV）的一部分存在；3）富含载脂蛋白E的载脂蛋白A-I:A-II和载脂蛋白A-I是HepG2细胞分泌的主要含载脂蛋白A的脂蛋白。
