Ruiz-Albusac J M, Velázquez E, Montes A
Department of Biochemistry, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
Clin Chem. 1988 Feb;34(2):240-3.
We studied the precipitation of isolated lipoproteins with heparin and MnCl2. Lipoproteins were isolated from human plasma by preparative ultracentrifugation and their free cholesterol was labeled. Each lipoprotein fraction was then precipitated at various pHs, with or without bovine serum albumin (60 g/L) present. Under no set of conditions was one class of lipoproteins completely separated from the other two. Specifically, under standard conditions for precipitation of serum lipoproteins (pH 7.4 and protein 60 g/L), 12% of the very-low-density lipoprotein (VLDL) and 8% of the low-density lipoprotein (LDL) remained in the supernatant liquid, and 30% of the high-density lipoprotein (HDL) was precipitated. These results indicate that, under these conditions, so-called HDL cholesterol may be a mixture of VLDL, LDL, and HDL, although the sum of the amount of these three fractions remaining in the supernate is fortuitously very close to the value for HDL cholesterol isolated by ultracentrifugation.
我们研究了用肝素和氯化锰对分离出的脂蛋白进行沉淀的情况。通过制备性超速离心从人血浆中分离脂蛋白，并对其游离胆固醇进行标记。然后在有或无牛血清白蛋白（60 g/L）存在的情况下，于不同pH值下对每个脂蛋白组分进行沉淀。在任何条件下，一类脂蛋白都无法与其他两类完全分离。具体而言，在血清脂蛋白沉淀的标准条件下（pH 7.4和蛋白质60 g/L），12%的极低密度脂蛋白（VLDL）和8%的低密度脂蛋白（LDL）留在上清液中，30%的高密度脂蛋白（HDL）被沉淀。这些结果表明，在这些条件下，所谓的HDL胆固醇可能是VLDL、LDL和HDL的混合物，尽管这三个组分留在上清液中的总量偶然地非常接近通过超速离心分离出的HDL胆固醇的值。
