Oxygen free radicals cause extensive chemical changes in DNA, includin
g base and sugar modifications and strand breaks, In the present study
we found that a mutagen, glyoxal, is produced by exposure of DNA to a
n oxygen radical forming system (5 mM FeSO4-EDTA, 37 degrees C, 60 min
), It was produced with 17 times higher efficiency than 8-hydroxydeoxy
guanosine. Thus it is possible that the formation of glyoxal is one of
the major types of damage in DNA exposed to oxygen free radicals.