One-electron oxidation of guanine and 2'-deoxyguanosine by the azide radical in alkaline solutions

¹ Department of Chemistry, Nuclear Research Centre-Negev, Beer-Sheva 84190, Israel.
² Department of Chemistry, Ohio State University, Columbus, Ohio 43210-1173, USA.

Abstract

The [math] radical specifically oxidizes 2'-deoxyguanosine at its guanylic moiety. The guanylic radical resulting from this one-electron oxidation is followed by a first-order kinetics process. This is distinctively observed in alkaline solutions (pH ≥ 11) where a new transient could be characterized. This transient exhibits spectra that are similar to those observed with guanine. It is suggested that the oxidized nucleoside radical undergoes a monomolecular process to form an oxidized guanine radical.

Résumé

Le radical [math] oxyde spécifiquement le fragment guanine de la désoxy-2' guanosine. Le radical ainsi formé suit un processus de premier ordre. Ce processus est clairement observé en milieu alcalin (pH ≥ 11) où un nouveau spectre transitoire a pu être mis en évidence. Ce spectre ressemble à celui observé pour la guanine. Nous proposons que le radical issu de l’oxydation du nucléoside suive une réaction monomoléculaire conduisant à un produit radicalaire d’oxydation de la guanine.