Characterization of free radical-induced base damage in DNA at biologically relevant levels
DNA damage induced by oxygen radicals, e.g., hydroxyl radicals generated in living cells either by cellular metabolism or external agents such as ionizing radiations, appears to play an important role in mutagenesis, carcinogenesis, and aging. Elucidation of the chemical nature of such DNA lesions at biologically significant quantities is required for the assessment of their biological consequences and repair. For this purpose, a sensitive method using gas chromatography-mass spectrometry with the selected-ion-monitoring technique (GC-MS/SIM) was developed in the present work. DNA was exposed to hydroxyl radicals and hydrogen atoms produced by ionizing radiation in N2O-saturated aqueous solution. DNA samples were subsequently hydrolyzed with formic acid, trimethylsilylated, and analyzed by GC-MS/SIM. Characteristic ions from previously known mass spectra of DNA base products as their trimethylsilyl derivatives were recorded and the area counts of each ion were integrated. From these acquired data, a partial mass spectrum of each product was generated and then compared with those of authentic materials. This technique permitted the detection and characterization of a large number of free radical-induced based products of DNA, i.e., 5,6-dihydrothymine, 5-hydroxy-5,6-dihydrothymine, 5-hydroxymethyluracil, 5-hydroxyuracil, 5-hydroxycytosine, thymine glycol, 4,6-diamino-5-formamidopyrimidine, 8-hydroxyadenine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, and 8-hydroxyguanine, simultaneously in a single sample after radiation doses from 0.1 to 10 Gy. Detectable amounts of the base products were found to be as low as approximately 10 fmol per injection.
- Research Organization:
- National Bureau of Standards, Gaithersburg, MD
- OSTI ID:
- 5092102
- Journal Information:
- Anal. Biochem.; (United States), Vol. 1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
CHEMICAL RADIATION EFFECTS
DNA REPAIR
HYDROGEN
HYDROLYSIS
HYDROXIDES
IONIZING RADIATIONS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELEMENTS
HYDROGEN COMPOUNDS
LYSIS
NONMETALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
SOLVOLYSIS
560111* - Radiation Effects on Biochemicals- In Vitro- (-1987)