Fig 5. Cyclic voltammograms recorded in 0.5 mM aqueous solution of Cu(II)-NSFRY-NH₂ complex (black solid line) and NSFRY-NH₂ peptide (black dashed line) at pH 6.0; Cu(II)-AAAAA-NH₂ complex (red solid line) and AAAAA-NH₂ peptide (red dashed line) at pH 6.5; Cu(II)-NSFRA-NH₂.