| Abstract: | Abstract— DNA purine modifications by ultraviolet irradiation have not been as extensively studied as those of pyrimidines. However, a number of such reactions have been identified. These include photochemical addition of amino acids, photoalkylation by alcohols, amines and other compounds, photochemical activation of procarcinogens to mutagenic electrophiles, and formation of covalent linkages between DNA purines and adjacent bases. The recent characterization of two adenine-adenine di-adducts and the finding of endonucleases from two sources that incise ultraviolet-irradiated DNA at purine photoproducts indicate the possible biological importance of these moieties. |
