Nucleobases, Nucleosides and Nucleotides - Free-Radical-Induced DNA Damage and Its Repair - page 299

O 2 ( 1

∆ g ) not only oxidizes dGuo to 8-oxo-G, but the latter reacts even two or-
ders of magnitude faster with this oxidant (Sheu and Foote 1995a), whereby the
4-hydroperoxide is formed via an unexpected rearrangement of the dioxetan
intermediate (Sheu and Foote 1995b). The water-soluble endoperoxide derived
from N , N -di(2,3-diydroxypropyl)-1,4-naphthalenedipropanamide is a clean

source of O 2 ( 1

′

∆ g ), and can even prepared with an 18 O label. Using this approach,
the oxygen label in the final products, Iz, Z, Sp and guanodinohydantoin was
detected (Martinez et al. 2002).
The dCyd oxidation products 5-hydroxy-dCyd and 5-hydoxy-dUrd have low
oxidation potentials (Wagner et al. 2004) and are hence likely to be oxidized fur-
ther. For this reason the oxidation of 4-hydroxy-dUrd has been studied (Rivière
et al. 2004). Using Br 2 or Na 2 IrBr 6 but also menadione plus UV as oxidants, the
main oxidation products were the isodialuric acid, dialuric acid and hydantoin
derivatives.

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