Sugiuchi H, Irie T, Uji Y, Ueno T, Chaen T, Uekama K, Okabe H
Department of Central Laboratory, Kumamoto University Hospital, Japan.
Clin Chem. 1998 Mar;44(3):522-31.
We have developed a fully automated method for measuring LDL-cholesterol (LDL-C) in human serum without the need for prior separation, using a nonionic surfactant, polyoxyethylene-polyoxypropylene block copolyether (POE-POP), and a sodium salt of sulfated cyclic maltohexaose, alpha-cyclodextrin sulfate. Of the surfactants tested, POE-POP with a higher molecular mass of the POP block and a greater hydrophobicity reduced the reactivity of cholesterol in lipoprotein fractions; the reactivity in descending order was LDL >> VLDL > chylomicron approximately HDL. Gel filtration chromatographic studies revealed that POE-POP removed lipids selectively from the LDL fraction and allowed them to participate in the cholesterol esterase-cholesterol oxidase coupling reaction system. By contrast, alpha-cyclodextrin sulfate reduced the reactivity of cholesterol, especially in chylomicrons and VLDL. A combination of POE-POP with alpha-cyclodextrin sulfate provided the required selectivity for the determination of LDL-C in serum in the presence of magnesium ions and a small amount of dextran sulfate without precipitating lipoprotein aggregates. There was a good correlation between the results of LDL-C assayed by the proposed method and the beta-quantification reference method involving 161 sera with triglyceride concentrations ranging from 0.3 to 22.6 mmol/L.
我们开发了一种全自动方法，用于测定人血清中的低密度脂蛋白胆固醇（LDL-C），无需事先分离，使用非离子表面活性剂聚氧乙烯-聚氧丙烯嵌段共聚物（POE-POP）和硫酸化环麦芽六糖的钠盐α-环糊精硫酸盐。在所测试的表面活性剂中，具有较高分子量的POP嵌段和更大疏水性的POE-POP降低了脂蛋白组分中胆固醇的反应性；反应性从高到低依次为LDL >> VLDL > 乳糜微粒≈HDL。凝胶过滤色谱研究表明，POE-POP从LDL组分中选择性地去除脂质，并使其参与胆固醇酯酶-胆固醇氧化酶偶联反应体系。相比之下，α-环糊精硫酸盐降低了胆固醇的反应性，尤其是在乳糜微粒和VLDL中。POE-POP与α-环糊精硫酸盐的组合为在存在镁离子和少量硫酸葡聚糖的情况下测定血清中的LDL-C提供了所需的选择性，且不会沉淀脂蛋白聚集体。用该方法测定LDL-C的结果与涉及161份甘油三酯浓度范围为0.3至22.6 mmol/L血清的β-定量参考方法的结果之间具有良好的相关性。
