Experimental and Theoretical Prediction of The Redox Potential of Dopamine and Its Supramolecular Complex With Glycine

Abstract

The redox reaction of catecholamine is a two-proton-two-electron reaction in aqueous solution. N-protonated dopamine (DA) can be oxidated to N-protonated dopamine quinone (DAquinone). The standard electrode potential (E°) value of DA/DAquinone couple is obtained experimentally with cyclic voltammetry (CV) and theoretically with two methods at B3LYP/6-311++G(d,p) level. The theoretical E° value of DA/DAquinone couple is in good agreement with experimental one and close to each other. Glycine (Gly) is the simplest amino acid, and it can form hydrogen bonds with DA in physiological environment. The E° value of DA-Gly/DAquinone-Gly couple is predicted experimentally and theoretically. We find that the E° value of DA-Gly/DAquinone-Gly couple is larger than DA/DAquinone couple. Hydrogen bond interaction weakens the electron-donation abilities of DA.