The melanin pigments occurring in the hair and skin of mammals are classified as either eumelanins or pheomelanins; eumelanins are black or dark brown, whereas pheomelanins are lighter red-brown or yellow pigments. Both are high-molecular-weight polymers of poorly defined structure? Melanins catalyze several redox reactions: and it has been suggested that such chemical reactivity may play an important role in the protective action of melanin ...
