POTENTIOMETRIC DETERMINATION OF FORMATION-CONSTANTS OF COPPER(II) BILE ACID/PEPTIDE IN AQUEOUS-SOLUTION/

A potentiometric method was used to study the equilibria in aqueous so lution for the systems copper(II)/bile acid salt/peptide [bile acid sa lt-sodium cholate or glycocholate; and peptide-glutamic acid (glutamat e), glutamine or glutamylglutamic acid], specifically to assess cooper ative binding between small peptides and bile acids in the presence of copper(II). The results obtained suggest large cooperativity in forma tion of ternary complexes with amino acids when they are coordinated t o copper(II) as bidentate ligands.