Photooxidation thymidine

Wagner J.R., van Lier J.E., Johnston L.J., Quinone sensitized electron transfer photooxidation of nucleic acids Chemistry of thymine and thymidine radical cation in aqueous solution, Photochem. Photobiol., 1990,52, 333-343. 

It is well established that singlet oxygen is able to oxidise DNA with a much higher specificity than hydroxyl radical. The main stable oxidation products of the reaction of O2 with 2-deoxyribose guanine were identified as the and 4S diastereoisomers of 4-hydroxy-8-oxo-4,8-dihydro-2 -deoxy-guanosine on the basis of extensive NMR and mass spectrometry measurements (Ravanat et al. 1992, Ravanat and Cadet 1995). Similar oxidation products were generated by the type II photooxidation reaction of 2 -deoxyguanosylyl -(3 -5 )-thymidine (Buchko et al. 1992). 

---