Yamamoto M, Ranganathan S, Kottke B A
Biochem Int. 1985 Oct;11(4):573-81.
Very low density lipoproteins (VLDL) from normolipidemic subjects were able to bind to the cultured human skin fibroblasts almost as efficiently as low density lipoproteins (LDL). The rate of esterification of cholesterol in the fibroblasts was enhanced by VLDL to the same extent as by LDL. Trypsin treatment of VLDL abolished the binding capacity completely. When trypsin-treated VLDL was partially delipidated with heptane, part of the binding capacity to the fibroblasts was restored. SDS polyacrylamide gel electrophoresis showed that apolipoprotein E (apo E) in VLDL was digested completely by trypsin. Although normal VLDL are recognized by the cells through apolipoprotein E, the major apoprotein of VLDL, that is apolipoprotein B (apo B), is not functional unless the core triglycerides are removed. In contrast to the previous reports which indicate that only hypertriglyceridemic VLDL and not normal VLDL interact with fibroblast receptors, our results clearly show that VLDL from normolipidemic subjects can also bind to these receptors.
来自血脂正常受试者的极低密度脂蛋白（VLDL）与培养的人皮肤成纤维细胞结合的效率几乎与低密度脂蛋白（LDL）相同。VLDL使成纤维细胞中胆固醇的酯化速率提高到与LDL相同的程度。用胰蛋白酶处理VLDL会完全消除其结合能力。当用庚烷对经胰蛋白酶处理的VLDL进行部分脱脂时，其与成纤维细胞的部分结合能力得以恢复。十二烷基硫酸钠聚丙烯酰胺凝胶电泳显示，VLDL中的载脂蛋白E（apo E）被胰蛋白酶完全消化。尽管正常的VLDL通过其主要载脂蛋白即载脂蛋白B（apo B）被细胞识别，但除非核心甘油三酯被去除，否则apo B无功能。与之前报道仅高甘油三酯血症的VLDL而非正常VLDL与成纤维细胞受体相互作用不同，我们的结果清楚地表明，血脂正常受试者的VLDL也能与这些受体结合。
