E.P.R. of Free Radicals Formed in DNA and Its Constituents after Exposure to Discharge-excited Inert Gases

Summary

The mechanisms of radical formation in the purine bases, nucleosides and nucleotides of DNA as well as in DNA itself after exposure to discharge-excited inert gases were investigated by means of e.p.r. spectroscopy. In contrast to gamma-irradiation, no ionization products could be identified. From the results it is concluded that radical formation is due to dissociation of atomic hydrogen from the bases. The spectra of the base fragments formed in this way could be observed together with those of hydrogen addition radicals due to the reaction of the hydrogen atoms.