Grinstead G F, Ellefson R D
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905.
Clin Chem. 1988 Jun;34(6):1036-40.
We have purified Lp(a) lipoproteins from sera of four subjects by ultracentrifugation, selective precipitation, and chromatofocusing. Each subject had two forms of serum Lp(a) that were separable by chromatofocusing. We purified apolipoprotein (a) [apo(a)] from the eight isolated Lp(a)s and obtained only one form of apo(a) from each subject. The four apo(a)s seen on sodium dodecyl sulfate-polyacrylamide gel electrophoresis had different apparent molecular masses, ranging from 275 to 440 kDa. Chemical deglycosylation of the smallest apo(a) yielded a 235 kDa protein, which may be a core protein structure common to all apo(a)s. We conclude that there are many forms of serum Lp(a) and apo(a). The heterogeneity of serum Lp(a) particles can be ascribed in part to differences in size of apo(a), but other factors must account for the existence within a single patient of different Lp(a)s that contain apparently identical apo(a). One must consider the heterogeneity of Lp(a) when designing assays for this lipoprotein.
我们通过超速离心、选择性沉淀和色谱聚焦法从四名受试者的血清中纯化了脂蛋白(a)[Lp(a)]。每个受试者的血清Lp(a)有两种形式，可通过色谱聚焦法分离。我们从八个分离的Lp(a)中纯化了载脂蛋白(a)[apo(a)]，每个受试者仅获得一种形式的apo(a)。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上看到的四种apo(a)具有不同的表观分子量，范围从275到440 kDa。最小的apo(a)经化学去糖基化后产生一种235 kDa的蛋白质，这可能是所有apo(a)共有的核心蛋白质结构。我们得出结论，血清Lp(a)和apo(a)有多种形式。血清Lp(a)颗粒的异质性部分可归因于apo(a)大小的差异，但其他因素必定是单一患者体内含有明显相同apo(a)的不同Lp(a)存在的原因。在设计针对这种脂蛋白的检测方法时，必须考虑Lp(a)的异质性。
