IMPROVED METHOD FOR THE SEPARATION OF PEPTIDES AND ALPHA-AMINO-ACIDS ON COPPER-SEPHADEX

An improved method for the separation of peptides from large amounts of α-amino acids on copper-Sephadex is described. The separation is essentially dependent upon the copper content of Sephadex, the pH of the system, and the concentration of the sample, and it is due to the different stabilities of copper complexes of Sephadex, peptides, and α-amino acids. Sephadex behaves as a solid ligand. Compounds that form weaker complexes with copper than Sephadex apparently move with the solvent front. α-Amino acids that form copper complexes having a stability comparable to that of copper-Sephadex complexes are retained on the column. Peptides form strong complexes, stripping copper from the column. They are only slightly retained. The method is most practical when copper is removed from the eluates with chelating ion-exchanger Dowex A-1. Examples are given for the chromatography of single compounds, model mixtures, and extracts from cheese and yeast. © 1979.