Human chorionic gonadotropin. I. Purification and physicochemical properties.

Abstract

A highly active preparation of human chorionic gonadotropin has been obtained by simple methods of column chromatography on diethylaminoethyl Sephadex and Sephadex G-100. The preparation appeared homogeneous by disc and immunoelectrophoresis, ultracentrifugation, and end group analysis. It assayed at 12,000 i.u. per mg by the rat prostrate gland and accessory sex organ method. The s20, w value was found to be 2.89 S. A molecular weight of 59,000 ± 4,000 was determined by gel filtration on Sephadex G-150. However, the sedimentation equilibrium method gave a value of 47,000 ± 3,000. The molecular weight of the reduced carboxamidomethylated human chorionic gonadotropin, determined by gel filtration, was 30,000 ± 2,000, indicating that human chorionic gonadotropin was probably composed of two polypeptide chains. The minimal molecular weight, computed from the chemical composition, was 27,000. The amino acid and carbohydrate composition of the hormone has been determined.