Amino-Acids in Posterior Pituitary Protein

Abstract

THE protein isolated from the pars neuralis of the pituitary by van Dyke et al.¹ contains 1 I.U. per 61 µgm. Pressor, antidiuretic and oxytocic activities are present in constant amounts and in the same ratio found in crude posterior pituitary powder. This protein contains 4.3 per cent sulphur which appeared to be entirely in cystine. It seemed of interest to confirm the earlier conclusion that cystine is the only sulphur-containing amino-acid in the protein and to identify qualitatively as many amino-acids as possible.