Electrochemical oxidation of guanosine and adenosine: Two convergent pathways

We herein explore a novel route for oxidative stress in DNA by using electrochemistry as mimicking tool. Essentially, the electrochemical oxidation of guanine and adenine nucleosides and oligo-homo-nucleotides at pyrolytic graphite electrodes in neutral and alkaline aqueous solutions was studied. Under these experimental conditions all these compounds give rise to an adsorbed product not previously described, which was electrochemically and kinetically characterized. The virtually identical kinetic and electrochemical features exhibited by the oxidized compounds generated from all precursors strongly suggest a common species arising from both adenine and guanine derivatives. Supported by DFT calculations, we propose two convergent pathways for the electrochemical oxidation of adenosine and guanosine. Those calculations indicate that the common oxidized base product forms stable H-bond base pairs with both thymine and cytosine.