Transformation of albumin into melanin by hydroxyl radicals.

Bovine serum albumin (BSA) was exposed to hydroxyl radicals generated by the Fenton reaction. The reaction of the BSA solution with hydroxyl radicals resulted in a colour change from clear transparent to dark brown. The reaction was followed spectrophometrically. It was observed that during the reaction of BSA with hydroxyl radicals, a melanin-like absorption spectrum developed. The reaction with ferricyanide and the dark brown BSA solution resulted in the same dark blue-green colour as is typical for melanin. The results suggest that, by the reaction of BSA with hydroxyl radicals, melanin was formed.