Radiation chemistry of the nucleobases

Abstract

Publisher Summary This chapter focuses on the radiation-induced free-radical chemistry of the nucleobases and some of their derivatives, which , on one hand, comprises of nucleosides and nucleotides, and model compounds such as some methylated nucleobases on the other. The radiolytic studies of the nucleobases are carried out to establish a kinetic image of the interplay of the processes that are induced by the action of radiation and to find out the products that are generated. In an aqueous solution, the nucleobases react with the OH radical and the solvated electron at close to diffusion-controlled rates, while the H atom reacts one order of magnitude more slowly. The nucleobases, like all unsaturated systems, react with the water radicals OH and H mostly by addition. Radical cations are the primary products when the energy of ionizing radiation is deposited in the DNA molecule. For this reason, their chemical behavior is of considerable interest. In aqueous solution, nucleobase radical cations, or their conjugate bases, may be produced by hydroxide, or water, elimination from the OH-adduct radicals. The method of choice to produce them for the purpose of their study is to make the nucleobases or their derivatives react with strongly oxidizing radicals.