Purification and properties of choriogonadotropin from human term placenta.

Affinity chromatography has been applied successfully to the isolation of human choriogonadotropin from human term placenta. In a single step, a 57-fold purification was achieved. Evidence is presented which indicates that the product contains intact hormone as well as its free alpha-subunit. Preliminary data suggest that a variant form of alpha-subunit is also present which has serine as its N-terminal and contains relatively little arginine and proline as compared to the authentic alpha-subunit.