Purification and Characterization of Human Chorionic Gonadotropin

Abstract

A purified preparation of human chorionic gonadotropin has been obtained by techniques of alcohol precipitation, ion exchange chromatography and gel filtration. Evidence is presented that the product is homogeneous in size and amino acid composition, but heterogeneous in electrical charge and sialic acid content. The polypeptide portion of the molecule has a high proline content (12.6 moles/mole of HCG) and appears to be composed of 2 identical subunits, each with a molecular weight in the range of 25,000 to 28,000. The biological activity of the purified material is in the range of 13,700 to 18,600 IU/mg. (Endocrinology 84: 298, 1969)