Isolation and identification of thymine products from DNA. gamma. irradiated in oxygen-free aqueous solutions

Journal Article · Wed Oct 11 04:00:00 EDT 1978 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00489a034· OSTI ID:6600568

Teoule, R; Bonicel, A; Bert, C; Fouque, B

A solution of Escherichia coli DNA /sup 14/CH/sub 3/ labelled in the thymine moiety was deaerated under vacuum by repeated cycles of freezing and pumping; sample was irradiated in sealed vial by /sup 60/Co ..gamma.. rays with a dose rate of 70 Gy/m at Gy(gy = gray). The resulting polymeric material was separated from the low-molecular weight material by dialysis. Formic acid hydrolysis of the high-molecular weight material yielded thymine, 5,6-dihydrothymine, cis- and trans-5,6-dihydroxythimine, and 5-hydroxy-5,6-dihydrothymine. The initial step of a proposed mechanism involves the formation of hydroxyl radicals, hydrogen atoms, and hydrated electrons, which are formed when water absorbs gamma rays. These species are short-lived and react with DNA. The hydroxyl radicals attack both the C-5 and C-6 sites of the thymine ring; the hydrated electrons react pyrimidine to form ions which then undergo protonation; and hydrogen atoms add preferentially at C-6. The pyrimidine radicals are then able to undergo electron transfer through a dismutation reaction. Solvolytic substitution of the pyrimidic ions and hydrogen atom exchange produce the final reaction products.

• Research Organization: CEA/CEN, Grenoble, France
• OSTI ID: 6600568
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 100:21; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
560100 -- Biomedical Sciences
Applied Studies-- Radiation Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANAEROBIC CONDITIONS
AQUEOUS SOLUTIONS
AZINES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14
CARBON ISOTOPES
CARBOXYLIC ACIDS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DIALYSIS
DISPERSIONS
DNA
DOSE RATES
ELECTROMAGNETIC RADIATION
ELECTRON TRANSFER
ELECTRONS
ELEMENTARY PARTICLES
ESCHERICHIA COLI
EVEN-EVEN NUCLEI
FERMIONS
FORMIC ACID
GAMMA RADIATION
HETEROCYCLIC COMPOUNDS
HYDROGEN IONS
HYDROLYSIS
HYDROXY COMPOUNDS
HYDROXYL RADICALS
INFRARED SPECTRA
IONIZING RADIATIONS
IONS
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LABELLING
LEPTONS
LIGHT NUCLEI
LYSIS
MAGNETIC RESONANCE
MASS SPECTRA
MICROORGANISMS
MIXTURES
MONOCARBOXYLIC ACIDS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
POLYMERS
PYRIMIDINES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOISOTOPES
RADIOLYSIS
REACTION INTERMEDIATES
REACTION KINETICS
RESONANCE
SEPARATION PROCESSES
SOLUTIONS
SOLVATED ELECTRONS
SOLVOLYSIS
SPECTRA
THYMINE
ULTRAVIOLET SPECTRA
URACILS
YEARS LIVING RADIOISOTOPES
YIELDS