Liu H, Malhotra V, Ryan R O
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Biochem Biophys Res Commun. 1991 Sep 16;179(2):734-40. doi: 10.1016/0006-291x(91)91878-g.
A hybrid low density lipophorin particle (LDLp) was prepared by incubation with human apolipoprotein (apo) A-I in vitro. ApoA-I associated with LDLp in a concentration dependent, saturable manner which was accompanied by dissociation of apolipophorin III (apoLp-III). The apoA-I hybrid LDLp had the same lipid composition, density and morphology as native LDLp indicating that displacement of apoLp-III by apoA-I did not affect its structural properties. The molar ratio of apoLp-I:apoLp-II:apoLp-III was maximally reduced from 1:1:16 to 1:1:2 in native versus hybrid LDLp with the latter particle binding 7 molecules of apoA-I. The inability of apoA-I to displace the remaining 2 apoLp-III supports the concept that these apoLp-III molecules are not equivalent to the other fourteen. Native and hybrid LDLp particles were both metabolized to high density lipophorin in vivo. The displacement reaction represents a novel method for the production of apolipoprotein hybrids of LDLp and the results indicate that apoA-I has an inherently higher affinity for lipid surfaces than apoLp-III.
通过在体外与人载脂蛋白（apo）A-I孵育制备了一种混合低密度脂蛋白颗粒（LDLp）。ApoA-I以浓度依赖性、可饱和的方式与LDLp结合，同时伴有载脂蛋白III（apoLp-III）的解离。ApoA-I杂交LDLp具有与天然LDLp相同的脂质组成、密度和形态，表明apoA-I取代apoLp-III并不影响其结构特性。在天然LDLp与杂交LDLp中，apoLp-I:apoLp-II:apoLp-III的摩尔比从1:1:16最大程度降低至1:1:2，后者颗粒结合7个ApoA-I分子。ApoA-I无法取代剩余的2个apoLp-III，这支持了这些apoLp-III分子与其他14个分子不等同的概念。天然和杂交LDLp颗粒在体内均被代谢为高密度脂蛋白。这种取代反应代表了一种生产LDLp载脂蛋白杂交体的新方法，结果表明ApoA-I对脂质表面的亲和力本质上高于apoLp-III。
