Human pituitary thyrotropin. The primary structure of the alpha and beta subunits.

The amino acid sequence of the alpha and beta subunits of human pituitary thyrotropin has been proposed based on the data derived from the tryptic and chymotryptic peptides. The alpha subunit consists of 89 amino acid residues with two carbohydrate moieties, presumably linked to asparagines in position 49 and 75, and its amino acid sequence is identical to that of lutropin alpha. The beta subunit has 112 residues with a single carbohydrate moiety attached to asparagine at position 23. Comparison of the primary structure of human thyrotropin beta with that of the bovine hormone reveals that only 11 residue positions have been found to be different.