The formation of glycine and serine; the influence of the administration of glycine, DL-serine and other compounds on levels of tissue glycine and serine.

The rates of conversion of glycine into serine and serine into glycine have been determined by administration of isotopically labelled glycine and serine (Arnstein & Neuberger, 1953; Elwyn & Sprinson, 1954; Arnstein & Keglevi6, 1956; Arnstein & Stankovid, 1956). The present investigation, which is concerned with the net synthesis of glycine from serine, and of serine from glycine, was carried out with unlabelled glycine and serine and the methods were similar to those used in a previous investigation of tissue-glycine levels (Simkin & White, 1957). Greenberg & Sassenrath (1955) have made a more extensive but less detailed investigation of the effect of administration of several amino acids including glycine and serine.