Partial purification and characterization of a triacylglycerol-transfer protein from rabbit serum

Rabbit lipoprotein-free serum was found to contain a protein fraction that mediates the transfer of [3H]triacylglycerol from low-density lipoprotein to high-density lipoprotein. Fractionation of rabbit lipoprotein-free serum by DEAE-Sephadex chromatography, ammonium sulphate precipitation, concanavalin-A-Sepharose chromatography, Sephadex G-200 gel filtration, phenyl-Sepharose chromatography and Sephadex G-100 gel filtration, yielded a preparation that had a 500-fold increase in transfer activity compared to that of the starting sample. The transfer activity appeared to reside in a glycoprotein of molecular weight in the range 100 000-155 000 and an isoelectric point at pH 9.