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

Journal Article · Wed Oct 11 00:00:00 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), Vol. 100:21
• Country of Publication: United States
• Language: English

Related Subjects

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