Formation of malonaldehyde and acetaldehyde from the oxidation of 2'-deoxyribonucleosides.

2'-Deoxyribonucleosides, ribonucleosides, nucleobases, deoxyribose, and ribose were oxidized with Fenton's reagent. Malonaldehyde (MA) formed was derivatized with N-methylhydrazine to N-methylpyrazole, and acetaldehyde formed was derivatized with cysteamine to 2-methylthiazolidine. The resulting nitrogen-containing derivatives were quantitatively analyzed using gas chromatography with a nitrogen-phosphorus detector. MA and acetaldehyde were found in 2-deoxy-D-ribose and 2'-deoxyribonucleosides but not in ribonucleosides, nucleobases, and D-ribose. Amounts of MA formed from four deoxynucleosides were in the following order: 2'-deoxyguanosine > 2'-deoxycytidine > 2'-deoxyadenosine > or = thymidine. Amounts of acetaldehyde formed from four deoxynucleosides were in the following order: 2'-deoxycytidine > thymidine > 2'-deoxyadenosine > or = 2'-deoxyguanosine. The results suggest that the formation of MA and acetaldehyde requires a deoxy group on carbon 2' of a ribose moiety.