Scanu A M
Department of Medicine, University of Chicago, IL 60637.
Clin Chem. 1995 Jan;41(1):170-2.
Lipoprotein(a) [Lp(a)], a variant of low-density lipoprotein, is heterogeneous in density because of variability in the content and composition of its core lipids and size polymorphism of its specific glycoprotein component, apolipoprotein(a) [apo(a)]. In some individuals, density polymorphism may also derive from the fact that Lp(a) contains 2 mol of apo(a) per mole of apoB100, contrary to the more common 1:1 molar stoichiometry. Moreover, the size of apo(a) is polymorphic because of variations in the number of kringle 4 type 2 repeats. Another type of apo(a) polymorphism is related to sequence mutations at the kringle level. Two mutations can occur in kringle 4 type 10: one, Trp72-->Arg, is affiliated with an Lp(a) that is lysine-binding defective; the other, Met66-->Thr, with a normal lysine-binding function. Thus, Lp(a) is structurally and functionally polymorphic, a notion that must be considered in assessing the cardiovascular pathogenicity of this lipoprotein variant and in immunoquantification assays.
脂蛋白(a)[Lp(a)]是低密度脂蛋白的一种变体，由于其核心脂质含量和组成的变异性以及其特异性糖蛋白成分载脂蛋白(a)[apo(a)]的大小多态性，其密度具有异质性。在一些个体中，密度多态性也可能源于Lp(a)每摩尔载脂蛋白B100含有2摩尔apo(a)这一事实，这与更常见的1:1摩尔化学计量比不同。此外，由于kringle 4 2型重复序列数量的变化，apo(a)的大小具有多态性。另一种apo(a)多态性类型与kringle水平的序列突变有关。kringle 4 10型可发生两种突变：一种是Trp72→Arg，与赖氨酸结合缺陷的Lp(a)相关；另一种是Met66→Thr，具有正常的赖氨酸结合功能。因此，Lp(a)在结构和功能上具有多态性，在评估这种脂蛋白变体的心血管致病性和免疫定量分析中必须考虑这一概念。
