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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-11-16
pubmed:abstractText
The yields of strand break formation (Gssb) in single-stranded DNA (ssDNA) initiated by radiation-generated OH radicals have been determined using the method of low-angle laser light scattering (LALLS). The irradiations were carried out in aqueous, N2O-saturated solutions in the absence and presence of oxygen and at different concentrations of glutathione (GSH). GSH exhibits a protective effect, which is shown to be mainly due to OH radical scavenging. To quantify this, the rate constants for the reactions of OH with GSH and DNA have been redetermined under our experimental conditions. The values obtained were 9.0 x 10(9) and 4.5 x 10(8) dm3 mol-1 s-1, respectively. From the Gssb values obtained under anoxic conditions it is concluded that GSH protects against strand breakage (in addition to OH scavenging) by reacting with DNA radicals in competition to strand break formation. The rate constant of the repair reaction is 8.1 x 10(4) dm3 mol-1 s-1 at room temperature. For irradiations carried out in the presence of oxygen the rate of strand break formation is determined by the decay of DNA peroxyl radicals. Under these conditions we observed no protective effect of GSH apart from OH radical scavenging. The results are compatible with those that are expected from the oxygen-fixation hypothesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0955-3002
pubmed:author
pubmed:issnType
Print
pubmed:volume
58
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
589-602
pubmed:dateRevised
2001-11-13
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
The influence of glutathione on single-strand breakage in single-stranded DNA irradiated in aqueous solution in the absence and presence of oxygen.
pubmed:affiliation
Max-Planck Institut für Strahlenchemie, Mülheim a.d. Ruhr, FRG.
pubmed:publicationType
Journal Article