The microheterogeneity of human chorionic gonadotropin (HCG) reflected in the beta-subunits.

It is now evident that human chorionic gonadotropin (hCG) is not a single molecular entity but consists of a number of different biologically active components [l-4]. By means of gel isoelectric focusing 6 hCG forms recently could be isolated and characterized [2-41. Furthermore it is well established that hCG is composed of 2 subunits: hCG-a (common to other proteohormones) and hCH-fl (hormone specific) [5,6]. The correlation, however, between the microheterogeneity of the intact hormone and the subunits was not clear. We therefore wish to present data about the interrelationship between the hCG isohormones, the subunits, and sialic acid-free hCG.