Applications of Irreversible Photooxidation

Arizona State University, Scottsdale AZ

Investigators

Abstract

With the support of the Organic and Macromolecular Chemistry Program, Professor Ian Gould, of the Department of Chemistry and Biochemistry at Arizona State University, is studying applications of irreversible photooxidation in the elucidation of the mechanisms of oxidative processes in DNA. N-O bond cleavage of N-alkoxyheterocycles affords the radical cation of the parent heterocycle and an alkoxy radical. These irreversible photocleavage reactions allow exploration of the reaction chemistry of each of these reactive species. Following elucidation of the mechanisms and scope of the photochemistry of N-alkoxyheterocycles, Professor Gould will determine the oxidation potentials and lifetimes of purine radical cations in duplex DNA and explore the factors controlling their reactivity. Finally, oxidative damage in DNA will be studied using a mechanistic approach based on accurate measurements of quantum yields, quantifying the absolute and relative efficiencies of single-strand cleavage via one-electron oxidation of purine bases and via radical abstraction from the sugar backbone. Oxidation of DNA leads to reactive intermediate species. Exploration of the fundamental reaction chemistry of these reactive intermediates will lead to a more detailed understanding of oxidative processes which are of central importance in DNA chemistry and biochemistry. By developing unique reagents allowing the efficient formation of oxidized DNA species, Professor Ian Gould, of the Department of Chemistry and Biochemistry at Arizona State University, is exploring the reaction chemistry of these important but only transiently existent reactive intermediates.