Accession Number : ADA008148


Title :   Free Radical-Induced Chain Breakage in Irradiated Aqueous Solutions of DNA,


Corporate Author : ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD


Personal Author(s) : Meaburn,G. M. ; Cole,C. M.


Report Date : MAR 1974


Pagination or Media Count : 21


Abstract : The extent of chain breakage induced by free radical attack of calf thymus DNA in dilute aqueous solution has been determined by assay of liberated phosphomonoester groups. The relative effectiveness of hydroxyl radicals and hydrated electrons as initiators of this type of damage was investigated in both native and denatured DNA exposed to 60Co gamma and 40 MeV electron radiation in the absence of oxygen. Approximately 8 percent of available OH and 6 percent of hydrated electrons react to produce chain breaks in double-stranded DNA, whereas these values are reduced to 5 percent and 1-2 percent respectively, for the denatured material. The double helical polynucleotide structure provides protection for reactive sites on the bases which are fully exposed to attaacking radicals in single-stranded DNA.


Descriptors :   *DEOXYRIBONUCLEIC ACIDS, *RADIATION EFFECTS, *RADIATION CHEMISTRY, DAMAGE, BIOCHEMISTRY, HYDROXYL RADICALS, NUCLEOTIDES.


Subject Categories : BIOCHEMISRTY
      RADIOBIOLOGY
      RADIATION AND NUCLEAR CHEMISTRY


Distribution Statement : APPROVED FOR PUBLIC RELEASE