Mechanism of dismutation of superoxide produced during autoxidation of melanin pigments.

The hydrogen peroxide produced during the autoxidation of melanin pigments has been measured using an oxidase electrode. The autoxidation has been shown to occur via the superoxide intermediate. The melanin pigment competes with superoxide dismutase for the scavenging of superoxide radicals. However, superoxide dismutase at high concentrations caused a substantial increase in the production of hydrogen peroxide, formed during melanin autoxidation. The implications of this finding are discussed in light of melanin's ability to function as a pseudo-dismutase.