EQUILIBRIUM STUDIES AND MOLECULAR RECOGNITION IN THE GLYCYLGLYCINE, DL-ALANYL-DL-ALANINE AND GLYCYL-L-LEUCINE 1,4,7,13,16,19-HEXAAZA-10,22-DIOXACYCLOTETRACOSANE COMPLEXES

Potentiometric studies of OBISDIEN in the presence and absence of copp er(II) ion and the peptides, glycylglycine, dl-alanyl-dl-alanine and g lycyl-l-leucine, were performed. Equilibrium constants for the formati on of peptide dinuclear copper( II)-OBISDIEN species are reported. The se dinuclear complex systems were characterized by potentiometric titr ation and UV-Vis spectrophotometric measurements. The dinuclear copper (II) -OBISDIEN complexes show much higher complexation for glycylglyci ne and dl-alanyl-dl-alanine compared with glycyl-l-leucine, and the pr esent work suggests which species could be effective in catalyzing hyd rolysis of these peptides.