Isolation and Characterization of the Subunits of Porcine Follicle-Stimulating Hormone

Abstract

The α and β subunits of porcine FSH were isolated and purified to homogeneity as judged by SDS disc gel electrophoresis. The isolated subunits had less than 1% of the biological activity of the native hormone but were capable of recombining to generate at least 23% of the activity of the native hormone. The molecular weights calculated from hydrodynamic properties were 12,600 for pFSHα and 17,200 for pFSHβ. Total carbohydrate (g/100 g) was 18.9 for α and 15.1 for β. The sialic acid content of α (3.8 g/100 g) exceeded that of β (0.2 g/100 g). The α subunit contained significantly more lysine, alanine phenylalanine and methionine and significantly less aspartic acid, threonine, valine, isoleucine, leucine and tryptophan than the β subunit. Evidence was found for N—terminal heterogeneity and an internal cleavage in the isolated a subunit.