Human pituitary thyrotropin: isolation and chemical characterization of its subunits

The subunits of human pituitary thyrotropin have been separated and purified by countercurrent distribution and exclusion chromatography. The NH₂-terminal sequence of the β subunit is identical to that of the β subunit of bovine thyrotropin. However, amino acid composition and peptide map of tryptic and chymotryptic digests as well as compositions of tryptic and chymotryptic peptides suggest that the amino acid sequence of the α subunit is identical to that of the α subunit of human interstitial cell stimulating hormone.