Comparative study of base damage induced by gamma radiation and Fenton reaction in isolated DNA

Both gamma-irradiation and Fenton reaction generate oxidising species that damage isolated DNA. The comparison of the distribution of oxidised bases suggested that the Fenton reaction produces hydroxyl radicals like ionizing radiation. However, the former process was also found to generate a reducing species that increased the yield of formamidopyrimidine derivatives at the expense of the 8-oxo compounds of purine bases. Another peculiarity of the Fenton reaction was its ability to induce the formation, though in very low yield, of the malonaldehyde-2'-deoxyguanosine adduct in DNA, likely via the formation of base propenals upon degradation of the 2-deoxyribose unit.