2'-Deoxyguanosine (DG) oxidation and strand-break formation in DNA by the radicals released in the photolysis of N-tert-butoxy-2-pyridone. Are tert-butoxyl or methyl radicals responsible for the photooxidative damage in aqueous media?
[reaction: see text] The photolysis of pyridone 3b (photo-Fenton reagent) in benzene releases tert-butoxyl radicals, which have been trapped by DMPO and EPR-spectrally identified. In aqueous solution, however, the fragmentation of the tert-butoxyl into methyl radicals prevails and the former radicals are of no direct consequence in the photooxidation of 2'-deoxyguanosine (dG) and pBR 322 DNA. The photooxidative damage of nucleic acids is caused by the oxyl radical species generated from the methyl radicals with oxygen.
Adam
Waldemar
W
Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany. adam@chemie.uni-wuerzburg.de
Marquardt
Stefan
S
Kemmer
Diana
D
Saha-Möller
Chantu R
CR
Schreier
Peter
P
D000438:Alcohols / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects*; D003849:Deoxyguanosine / Q000378:metabolism*; D005609:Free Radicals / Q000494:pharmacology; D008697:Methane / Q000031:analogs & derivatives* / Q000494:pharmacology; D010084:Oxidation-Reduction; D010782:Photolysis; D011728:Pyridones / Q000737:chemistry* / Q000528:radiation effects
D000438:Alcohols; D005609:Free Radicals; C449041:N-tert-butoxy-2-pyridone; D011728:Pyridones; C059688:alkoxyl radical; C051224:methyl radical; D003849:Deoxyguanosine; D008697:Methane