Crystal Structure of Glycyl-L-Alanine Hydrochloride

Abstract

IN the course of a programme of research into the crystal structures of simple synthetic peptides undertaken in the laboratories of the Wool Industries Research Association, glyeyl-L-alahine has been synthesized and the structure of its hydrochloride elucidated using two-dimensional methods. As indicated in an earlier communication¹, the hydrochloride and hydrobromide of glycyl-L-alanine are isomorphous, with the following cell constants: and from the systematic absences observed the space group may be inferred to be $P_{{\text{2}}_{\text{1}}}$. The density of the hydrochloride by flotation is 1.465 gm. cm.⁻³, which necessitates the presence of two molecules of peptide and two molecules of water of crystallization in the unit cell. The existence of the latter was confirmed analytically.