Competitive oxidation of 6-hydroxydopamine by oxygen and hydrogen peroxide

Simultaneous oxygen electrode and conventional polarographic measurements show the net concentration of hydrogen peroxide produced by air oxidation of 6-hydroxydopamine is considerably less than that predicted from the known stoichiometry of the reaction. This is due to competitive oxidation of 6-hydroxydopamine by the generated hydrogen peroxide. The presence of ascorbic acid in this reaction also results in significant decreases of hydrogen peroxide under most conditions. The implications of these results to the molecular mechanism of 6-hydroxydopamine neurotoxicity are discussed.