Peroxyl radicals of nucleic acids and their components

If free radicals add to the bases of nucleic acids or abstract a hydrogen atom from the sugar moiety, mainly carbon-centered radicals are formed. In the presence of oxygen such carbon-centered radicals are converted into the corresponding peroxyl radicals at nearly diffusion-controlled rates (k ≅ 2 x 109 M-1 s-1). Our knowledge of the free-radical chemistry of purines, especially in the presence of oxygen, is at present still very limited, so that this discussion must be restricted to pyrimidines and to the sugar moiety. This article attempts to make the reader familiar with some of the complexities of peroxy radical reactions and to give some examples of how such reactions are reflected in the degradation of the free components of nucleic acids, and to what extent such results may be extrapolated to the nucleic acids themselves. 30 refs., 1 tab