McCormick S P, Day W A, George P M
Pathology Department, Christchurch School of Medicine, Christchurch Hospital, New Zealand.
Biochim Biophys Acta. 1995 Aug 24;1258(1):49-56. doi: 10.1016/0005-2760(95)00096-u.
We have characterized the lipoproteins isolated from the plasma of a human subject who was heterozygous for a mutation yielding a truncated apolipoprotein B (apo-B32). The apo-B32 lipoproteins were isolated from the plasma high density lipoprotein (HDL) fraction by heparin-Sepharose chromatography. Although the chemical composition of the apo-B32-containing lipoproteins was similar to that of normal HDL, the mean diameter of the apo-B32 lipoproteins was larger than typical apo-AI-containing HDL particles. On agarose gels, the apo-B32 lipoproteins had pre-beta mobility similar to that of normal very low density lipoproteins. Analysis of the purified apo-B32 lipoproteins by SDS-polyacrylamide gel electrophoresis revealed the presence of both apo-AI and apo-E. In order to further analyze the properties of apo-B32, we developed an apo-B32 expression vector and generated stable rat hepatoma cell lines expressing apo-B32. In these cell lines, the apo-B32 protein was secreted in a d > 1.21 g/ml lipoprotein. Oleic acid supplementation of the cell-culture media had no measurable affect on the density distribution of the apo-B32 lipoproteins that were secreted by the cells.
我们对从一名人类受试者血浆中分离出的脂蛋白进行了特性分析，该受试者为一种产生截短载脂蛋白B（apo - B32）的突变的杂合子。通过肝素 - 琼脂糖层析从血浆高密度脂蛋白（HDL）组分中分离出apo - B32脂蛋白。尽管含apo - B32的脂蛋白的化学组成与正常HDL相似，但apo - B32脂蛋白的平均直径大于典型的含apo - AI的HDL颗粒。在琼脂糖凝胶上，apo - B32脂蛋白具有与正常极低密度脂蛋白相似的前β迁移率。通过SDS - 聚丙烯酰胺凝胶电泳对纯化的apo - B32脂蛋白进行分析，结果显示同时存在apo - AI和apo - E。为了进一步分析apo - B32的特性，我们构建了一个apo - B32表达载体，并建立了表达apo - B32的稳定大鼠肝癌细胞系。在这些细胞系中，apo - B32蛋白分泌到密度大于1.21 g/ml的脂蛋白中。向细胞培养基中添加油酸对细胞分泌的apo - B32脂蛋白的密度分布没有可测量的影响。
