Radiolysis of the double-stranded polynucleotides poly(A + U) and DNA in the presence of oxygen. [Gamma radiation]

Journal Article · Sat Oct 01 00:00:00 EDT 1977 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574554· OSTI ID:5237357

Michaels, H B; Hunt, J W

The reaction of O/sub 2/ with .OH adducts produced on poly(A + U) was studied by pulse radiolysis. In the presence of O/sub 2/, the absorption spectrum of the poly(A + U) .OH adduct decays to a new spectrum, with a rate constant of 5 x 10/sup 7/ M/sup -1/ sec/sup -1/. Solutions of poly(A + U) and DNA, in common with other polynucleotides, are sensitive to repetitive pulsing, and in the case of DNA, denaturation takes place and single-stranded regions and pieces are produced. The .OH adduct of native double-stranded DNA does not appear to react with O/sub 2/ on a time scale from microseconds to seconds, yet steady-state radiolysis experiments and analysis for peroxides show that DNA hydroperoxides are produced at low doses. The .OH adduct of heat denatured, single-stranded DNA reacts with O/sub 2/ as expected. The apparent lack of reaction of double-stranded DNA .OH adducts with O/sub 2/ is hard to understand, since a reaction with the radiosensitizer NPPN is clearly observable under similar conditions. Possible explanations for the experimental results are discussed.

• Research Organization: Ontario Cancer Inst., Toronto
• OSTI ID: 5237357
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 72:1; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CRYOGENIC FLUIDS
DECOMPOSITION
DNA
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GAMMA RADIATION
HYDROXYL RADICALS
IONIZING RADIATIONS
IRRADIATION
NONMETALS
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXYGEN
PULSED IRRADIATION
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS