Fluorescence of γ-irradiated DNA and Purines in Aqueous Solution

Summary

In γ-irradiated solutions of DNA a characteristic fluorescence is observed which is not present before irradiation. On the basis of the excitation and emission spectra, it is concluded that two fluorescing components are present. One (A) has an excitation maximum at 310 nm and an emission maximum at 400 nm, whereas the other (B) has excitation maxima at 280 nm and 360 nm and an emission maximum at 450 nm. Both components are also found in irradiated guanine solution, with approximately the same spectral characteristics as in DNA. Component (A) results from attack by OH radicals, whereas both OH and reducing radicals are involved in the formation of (B).