Effect of U.V. irradiation and of various chemical conditions on the oxidation of NADH by pheomelanins.

The oxidation reaction of NADH with synthetic and natural pheomelanins was studied under various physicochemical conditions in order to obtain information about the molecular steps involved in the electron transfer process. The comparison with the previous data on eumelanins suggests that the reaction pathways are the same and that the greater photosensitivity of pheomelanins, observed in other experiments, is manifested in the redox reactions with NADH as an increased formation of quinone groups and of superoxide anions.