REACTIONS OF CU(II) WITH GLYCINE AND GLYCYLGLYCINE IN AQUEOUS-SOLUTION AT HIGH-CONCENTRATIONS OF SODIUM-CHLORIDE

The complex equilibria between the Cu(II) ion and the amino acids glycine and alanine and the peptide glycylglycine are studied in aqueous solution at high concentrations of sodium chloride, where condensation of glycine to peptide molecules has been observed. Comparison of the species distribution at the conditions where this reaction takes place leads to the conclusion that Cu(II) is already complexed by chloride and glycine at very low pH values. The presence of chloride in the detected species, and its influence on their stability are discussed. © 1990.