DNA damage and oxygen radical toxicity

James A. Imlay, Stuart Linn

Research output: Contribution to journalArticlepeer-review


A major portion of the toxicity of hydrogen peroxide in Escherichia coil is attributed to DNA damage mediated by a Fenton reaction that generates active forms of hydroxyl radicals from hydrogen peroxide, DNA-bound iron, and a constant source of reducing equivalents. Kinetic peculiarities of DNA damage production by hydrogen peroxide in vivo can be reproduced by including DNA in an in vitro Fenton reaction system in which iron catalyzes the univalent reduction of hydrogen peroxide by the reduced form of nicotinamide adenine dinucleotide (NADH). To minimize the toxicity of oxygen radicals, the cell utilizes scavengers of these radicals and DNA repair enzymes. On the basis of observations with the model system, it is proposed that the cell may also decrease such toxicity by diminishing available NAD(P)H and by utilizing oxygen itself to scavenge active free radicals into Superoxide, which is then destroyed by Superoxide dismutase.

Original languageEnglish (US)
Pages (from-to)1302-1309
Number of pages8
JournalScience Science
Issue number4857
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • General


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