Open Access

Hermann Hartmann, Joachim Heidberg

• The kinetic data of the hydrolysis of some serine peptides in diluted hydrochloric acid and in pure water and of the rearrangement of O-glycyl-DL-serine to glycyl-DL-serine were determined. The hydrolysis of glycyl-DL-serine and DL-alanyl-DL-serine proceeds surprisingly rapidly in pure water as compared with the hydrolysis of those peptides in 0.5 N hydrochloric acid as well as the hydrolysis of glycyl-DL-alanine in purely aqueous solution. The O → N migration of the glycyl residue in O-glycyl-DL-serine which probably is an intermediate in the cleavage of glycyl-DL-serine in purely aqueous solution represents a three center reaction in which the nucleophilic attack on the O-peptide and peptide bond, respectively, involves a free basic amino group. The analogy between the serine peptide interconversion and the hydrolysis catalyzed by certain proteolytic enzymes is referred to. Under the conditions of freeze drying are formed in hydrochloric acid solutions of DL-alanyl-DL-serine O-peptide and depsipeptide.