Studies on Immunological Assay of Human Chorionic Gonadotropin. I. Purification and Immunological and Physicochemical Properties of Human Chorionic Gonadotropin

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Abstract
In order to obtain a large amount of immunologically homogeneous human chorionic gonadotropin (hCG), a method for its purification was devised; hCG of 5550 IU/mg (immunological activity) was obtained in 29% yield from a commerical crude hCG (immunological activity; 1550 IU/mg) by using column chromatography with DEAE-Sephadex A-25, Con. A-Sepharose, and Sephadex G-100. The purified hCG appeared to be homogeneous by the Ouchterlony immunodiffusion, immunoelectrophoresis and ultracentrifugation. The S20,W value was found to be 3.07 S. The Stokes'' radius of hCG was determined as 37 .ANG. by gel filtration on Sephadex G-150. The amino acid composition and the content of carbohydrate were approximately equal to the values of other purified samples, taking the biological activity as an index. However, disc electrophoresis analysis revealed 2 bands close to each other and analysis by isoelectrofocusing showed peaks of high specific activity at pH 3.90 and 4.05.