DNA and Double-Stranded Oligonucleotides - Free-Radical-Induced DNA Damage and Its Repair - page 362

Fig. 12.8. Products derived from C detected (or most likely formed, see text) in free-radical-dam-
aged DNA

Fig. 12.9. Products derived from A detected in free-radical-damaged DNA

base sites but requires nucleotide excision repair (NER). This study has been
extended to various biochemical aspects of the effects of this lesion such as gene
transcription (Marietta et al. 2002) and the ability of various enzymes to excise
this lesion (Jaruga et al. 2004). In the latter study, it has been shown that the cA
lesion can be fully released by a cocktail consisting of nuclease P1, snake venom
phosphodiesterase and alkaline phosphatase which is in some contradiction to
results obtained with a similar, but not identical, enzymatic cocktail (Romieu et
al. 1999a).
In -irradiated N 2 O-saturated DNA solution, 0.56 cA lesions per 10 6 bases are

formed per Gy (Dizdaroglu et al. 2001b). This is equivalent to a G value of 0.9

γ

10 −9 mol J −1 . The yield of the cA lesion is hence considerably lower than that of

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