Pussinen P, Jauhianinen M, Metso J, Tyynelä J, Ehnholm C
National Public Health Institute, Department of Biochemistry, Helsinki, Finland.
J Lipid Res. 1995 May;36(5):975-85.
Phospholipid transfer protein (PLTP) from pig plasma was purified to homogeneity using ultracentrifugation and a combination of hydrophobic-, heparin-Sepharose-, and anti-pig-PLTP-affinity chromatography techniques. The molecular weight of PLTP is 78,000 as estimated by SDS-PAGE and by gel filtration. The effect of pig plasma PLTP on the particle size distribution of either human or pig high density lipoprotein (HDL) was studied by incubating HDL with PLTP. Incubation of human HDL3 or pig HDL with the highly purified preparations of PLTP induced a conversion of the homogeneous HDL into two main populations of particles. The conversion products were isolated by ultracentrifugation at density 1.21 g/ml. The size changes were evident as analyzed by native gradient gel electrophoresis and by high resolution gel filtration. The diameters of the large and small particles formed were 10.8 nm and 7.6-7.9 nm, respectively. In addition, pig HDL conversion products included a third population of particles with a diameter of 11.5 nm. The degree of conversion was dependent on time and PLTP activity. Neither cholesteryl ester transfer protein nor lecithin:cholesterol acyltransferase activity could be detected in the PLTP preparations. The present study demonstrates that purified pig PLTP can act as a conversion factor: it has the ability to convert HDL into populations of large and small particles. The release of apoA-I is an essential part of the conversion process.
采用超速离心以及疏水层析、肝素-琼脂糖层析和抗猪磷脂转运蛋白亲和层析技术相结合的方法，将猪血浆中的磷脂转运蛋白（PLTP）纯化至同质。通过SDS-PAGE和凝胶过滤法估计，PLTP的分子量为78,000。通过将高密度脂蛋白（HDL）与人或猪的PLTP一起孵育，研究了猪血浆PLTP对人或猪HDL粒径分布的影响。将人HDL3或猪HDL与高度纯化的PLTP制剂一起孵育，可使均一的HDL转化为两个主要的颗粒群体。通过在密度为1.21 g/ml下超速离心分离转化产物。通过天然梯度凝胶电泳和高分辨率凝胶过滤分析，粒径变化明显。形成的大颗粒和小颗粒的直径分别为10.8 nm和7.6 - 7.9 nm。此外，猪HDL转化产物还包括直径为11.5 nm的第三种颗粒群体。转化程度取决于时间和PLTP活性。在PLTP制剂中未检测到胆固醇酯转移蛋白和卵磷脂胆固醇酰基转移酶活性。本研究表明，纯化的猪PLTP可作为一种转化因子：它有能力将HDL转化为大颗粒和小颗粒群体。载脂蛋白A-I的释放是转化过程的重要组成部分。
