Abstract
In this paper we report on the interaction between the Cu(II)ions and the histidine analogues of oxytocin. The studied His-analogues are characterized by presence of Tyr(2) or Phe(2) amino acid residues and free or protected N-terminal group. The use of potentiometric methods allowed for the determination of the stoichiometry of formed complexes and calculation of their stability constants. The number of spectroscopic measurements (UV-Vis, CD, NMR, fluorescence) together with the theoretical calculation enabled to obtain the structures of formed complexes and the influence of Tyr(2) amino acid residue on the efficiency of metal ion binding. (C) 2012 Elsevier B.V. All rights reserved.