Abstract
Photoreduction of ferricytochrome c in aqueous solution was investigated by flash photolysis in the presence and absence of indole or o-dimethoxybenzene, which were known as efficient electron-donors in photochemistry. Formation of ferrocytochrome c was confirmed with its characteristic absorption spectrum. In the presence of the electron-donor, the reduction was not completely depressed by a sufficient amount of nitrous oxide and about 20 per cent of reduction was still observed. The reduction was also observed in the absence of the electrondonor. The direct photoreduction and the reduction unrestrained with nitrous oxide were examined by effects of oxygen, nitrous oxide, hydrogen peroxide and optical filter. The results suggested that ferricytochrome c could be reduced by UV light through excitation of certain aromatic amino acid residues in the molecule and by hydroxyl radicals converted from hydrated electrons via reaction with nitrous oxide.
