An Improved Purification of Human Chorionic Gonadotropin

A newly improved method for obtaining a highly active human chorionic gonadotropin (HCG) has been developed. A crude HCG with an activity of about 3, 000 IU per mg was applied to an Amberlite CG-50 column equilibrated with 0.01 M ammonium acetate buffer, pH 5.0. This first purification procedure yielded two separate peaks. The pooled fraction under the 2nd peak was concentrated and further purified by the chromatography on Sephadex G-100 which was pretreated with 0.1 N hydrochloric acid. An activity of more than 20, 000 IU per mg of protein was obtained through this simple purification procedure. A homogeneous ultracentrifuge pattern was observed with our purified product, however, faint-stained minor components still remained in the disc gel electrophoresis for further investigation.