Copper complexes of metal binding domains of synthesized amyloid-beta peptides - A beta(1-16) and N-truncated A beta(4-16) containing a novel N-terminal FRH sequence, as well as its shorter mutants were characterized by cyclic voltammetry. The influence of the peptide sequence and peptide to copper molar ratio on the electrochemical properties of the obtained structures were studied and discussed. The reversibility of the studied redox processes in copper complexes with A beta(4-x) derivatives was also investigated. The results indicate the crucial role of Tyr10 in the redox process of the A beta(4-x) complex, including the removal of reversibility of the Cu(II)/Cu(III) redox couple. (C) 2016 The Electrochemical Society. All rights reserved.