Hydroxyl Free Radical Mediated Strand Breaks in PBR322 Plasmid DNA
Oxygen free radicals react with and cause damage to DNA. Hydroxyl free radicals (·OH) add to DNA to yield several products, one of which is 8-hydroxydeoxyguanine (1). Digestion of DNA to the nucleoside level yields 8-hydroxydeoxyguanosine (8-OHdG) which can be very sensitively quantitated (to 20 femtomoles) by HPLC-electrochemical detection (2,3). The potential significance of the 8-OHdG adduct in living systems has been demonstrated by its presence in the DNA of human granulocytes following TPA-stimulated oxidative damage (3). The amount of 8-OHdG present in the granulocyte DNA was decreased by the addition of superoxide dismutase and/or catalase, thus emphasizing that oxygen free radical intermediates are the responsible agents (3).
KeywordsDouble Strand Break Hydroxyl Free Radical Supercoiled Plasmid Strand Scission Cetylpyridinium Bromide
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- 2.R.A. Floyd, J.J. Vatson, P.K. Wong, D.H. Altmiller, R.C. Rickard, Hydroxyl free radical adduct of deoxyguanosine: sensitive detection and mechanisms of formation. Free Radical Res. Commun. 1, 163–172 (1986).Google Scholar