Metal-catalyzed oxidation of protein-bound dopamine

The redox potential of the protein-bound dopamine (DA) is determined and a novel mechanism is developed for the oxidative modification of the protein, in which the DA-cysteine adduct causes oxidative modification of the DA-bound protein in the presence of [Cu.sup.2+]. The results have shown that the DA-modified protein might be involved in redox modification under oxidative stress, whereby DA covalently binds to cysteine residues, generating the redox-active cysteinyl-DA adduct that causes the metal-catalyzed oxidation of protein.