Purification of apolipoprotein H by polyethylene glycol precipitation

A new method of polyethylene glycol precipitation followed by heparin affinity chromatography was established to purify apolioprotein H (Ape H, beta(2)-glycoprotein I). This method is simple and effective and yields more harvest of Apo H (3-4 mg Apo H from 100 mi fetal bovine serum) than the current HClO4 extraction method. There are notable differences between Apo H purified by the polyethylene glycol method [Apo H (PEG)] and Apo H purified by the HClO4 method [Ape H (HClO4)] in respects of their SDS electrophoresis characteristics, circular dichroism spectroscopy, and isoelectric focusing graph. It is concluded that the strong acid HClO4 treatment may induce some disordered structure in Apo H molecule resulting in the lowering of molecular weight and pls. Apo H (PEG) retains more integrated structure which may be related to its bioactivity. (C) 1996 Academic Press, Inc.