Pregnant mare serum gonadotropin. Rapid chromatographic procedures for the purification of intact hormone and isolation of subunits.

A method exploiting hydroxylapatite chromatography was developed to purify pregnant mare serum gonadotropin (PMSG or eCG) to high biological activity from partially purified commerical preparations. In addition, an alternative method utilizing chromatography on quaternary aminoethyl (QAE)-Sephadex and Sephadex G-200 is also presented. Both procedures are capable of producing, from commerical material with a potency of approximately 2,500 IU/mg, a product in excess of 12,000 IU/mg. If care is taken in the selection of fractions from the hydroxylapatite chromatography, essentially purified material may be obtained in a single step. The best fraction from the QAE-Sephadex and G-200 chromatography procedure contains a minor impurity. Pregnant mare serum gonadotropin subunits were purified by a single chromatographic step from the foregoing preparations utilizing 6 M guanidine hydrochloride for dissociation, followed by chromatography on Sephadex G-75. Analytical data, including amino acid composition, carbohydrate composition. NH2-terminal amino acid determinations, and electrophoretic behavior of the subunits in sodium dodecyl sulfate polyacrylamide gel electrophoresis are presented.