Purification and characterization of apolipoprotein C-II from human plasma by high-pressure liquid chromatography

Apolipoprotein C-II, which activates lipoprotein lipase, was isolated from normal subjects and purified to homogeneity by reverse-phase high-pressure liquid chromatography (HPLC). The partially purified product from DEAE-cellulose chromatography was eluted from a Radial Pak C18 cartridge in a radial compression module using a linear gradient of 0.01 M ammonium bicarbonate and acetonitrile. The final product was homogeneous by polyacrylamide gel electrophoresis (pH 8.9), isoelectric focusing (pH 2.5-6.5), Ouchterlony double immunodiffusion, analytical HPLC and amino acid analysis. The purification of apolipoprotein C-II from normal subjects will permit the elucidation of its amino acid sequence and subsequent comparison with the known sequence of apolipoprotein C-II isolated from patients with hyperlipoproteinemia.