Interaction of Redox-Active Copper(II) with Catecholamines: A Combined Spectroscopic and Theoretical Study

In this work, attention is focused on the non-essential amino acid L-Tyrosine (TYR) hydroxylated to L-DOPA, which precursor neurotransmitters dopamine, noradrenaline (norepinephrine; NE) and adrenaline (epinephrine; EP) known as catecholamines their interactions with redox-active Cu(II). Catecholamines have multiple functions in biological systems, including regulation of central nervous system, free (unbound) redox metal ions are present many diseases disturbed homeostasis. The interaction between Cu(II) has been studied by means Electron Paramagnetic Resonance spectroscopy (EPR), EPR spin trapping UV-vis spectroscopy. obtained spectroscopic results supported Density Functional Theory calculations. Only minor qualitative quantitative changes spectra all compounds observed following ions. low-temperature were more convincing confirmed compounds, involving hydroxyl groups nitrogens. use an ABTS assay revealed that under study possessed radical-scavenging activities against ABTS•+ order TYR < EP DA NE~L-DOPA. DA, NE EP, Cu(II), exhibit ability (partially) reduce Cu(I) species was using specific chelator neocuproine. spin-trapping experiments suppressed formation radicals (•OH) a copper(II) catalyzed Fenton-like system presence catecholamines. case autooxidation stock solution observed. Furthermore, oxidation enhanced conclusion, it copper promotes cycling process, resulting ROS, may, turn, cause damage neuronal systems.