8-Hydroxyguanine is not produced by permanganate oxidation of DNA

Single-stranded M13mp2 DNA was oxidized with 0.8 mM KMnO4 at pH 8.6 and 4 degrees C for 5 min. These are conditions used previously by Akman et al. (Arch. Biochem. Biophys., 1990, 282, 202) for the oxidation of a denatured DNA and the authors reported that 8-hydroxyguanine was formed in the DNA with this treatment. We decomposed the oxidized DNA with heating in formic acid and the resulting bases were analyzed by HPLC. No significant 8-hydroxyguanine formation was detected in this sample. We also investigated the consumption of KMnO4 by nucleosides. Under conditions in which thymidine consumed KMnO4 rapidly, very little consumption was found with deoxyguanosine (less than 1/100, in rate, compared to that by thymidine). These results show that the permanganate oxidation of DNA does not result in the formation of 8-hydroxyguanine.