Isolation and characterization of human plasma lipid transfer proteins.

Abstract

A highly purified protein that facilitates the exchange and net mass transfer of cholesteryl ester (CE), and triacylglycerol (TG), and the transfer of phosphatidylcholine (PC), between plasma lipoproteins was isolated from the d-1.21-1.25 g/ml plasma fraction. Transfer activities showed similar distributions through ultracentrifugation, phenyl-Sepharose, DEAE-Sepharose, CM-cellulose, and hydroxyapatite chromatography. The lipid transfer protein appears to be an acidic protein with an apparent molecular weight of 64,000 +/- 1600 (n = 4) on sodium dodecyl sulfate polyacrylamide gel electrophoresis and an apparent molecular weight of 65,000 by gel filtration chromatography, and has a pI of 5.0 +/- 0.2 (n = 5) by both analytical isoelectricfocusing and chromatofocusing. The purified transfer protein facilitated the net mass transfer of CE from high density lipoprotein (HDL) or low density lipoprotein (LDL) to very low density lipoprotein (VLDL) and the net mass transfer of TG from VLDL to LDL or HDL. Chromato...