DNA and Double-Stranded Oligonucleotides - Free-Radical-Induced DNA Damage and Its Repair - page 395

product are Fe(III)BLM and the 4 aldehyde lesion mentioned above [reac-

tion (52)]. For a further reaction, the Fe(III)BLM has to be reactivated.

′ keto-1 ′

The formation of base propenals is not as straight-forward. From the above, it
is clear that O 2 is required for the formation of the base propenals. After the
formation of the C (4 ) peroxyl radical [reaction (53)], the Fe(IV)BLM species

has to interact with this peroxyl radical, possibly by forming an adduct [reaction
(54)]. The latter then decomposes and subsequently yields the products, the 3

′

-

′

phosphoglycolate, the base propenal and the 5 -phosphate terminus [reactions

(55)−(57)]. When reaction (53) is carried out with 18 O 2 , 18 O is incorporated into
the 3

′

-phosphoglycolate (McGall et al. 1987), while the carbonyl oxygen of the

′