Characterization of the purine ring-opened 7-methylguanine and its persistence in rat bladder epithelial DNA after treatment with the carcinogen N-methylnitrosourea
Journal Article
·
· Carcinogenesis (N.Y.); (United States)
Purine ring-opened 7-methylguanine, prepared in vitro by alkaline treatment of 7-methylguanosine or of methylated calf thymus DNA, was extensively characterized by chromatographic and spectral techniques as N5-methyl-N5-formyl-2,5,6-triamino-4-hydroxypyrimidine. This modified base chromatographed as an early-eluting peak on an ion-exchange column but separated into two interconvertible components after reversed-phase or porous-resin h.p.l.c. The two components were analyzed by thermal desorption mass spectrometry and 500 MHz 1H-N.M.R. spectroscopy. Their mass spectra were identical (M+ at m/z 183) and their N.M.R. spectra each exhibited the same two sets of resonances whose relative intensities were solvent-dependent. Analysis by h.p.l.c. showed interconversion of the two components and kinetic studies demonstrated that this reaction was a reversible first-order process. At equilibrium, k1 . k2 . 0.334 h-1 and delta G . 22.9 kcal/mol. These data indicated that the ring-opened 7-methylguanine exists as cis/trans isomers with restricted rotation about the amide bond.
- Research Organization:
- National Center for Toxicological Research, Jefferson, AR
- OSTI ID:
- 6627181
- Journal Information:
- Carcinogenesis (N.Y.); (United States), Journal Name: Carcinogenesis (N.Y.); (United States) Vol. 5:5; ISSN CRNGD
- Country of Publication:
- United States
- Language:
- English
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Composition and characterization of tRNA from Methanococcus vannielii
Journal Article
·
Tue May 16 00:00:00 EDT 1978
· Biochemistry; (United States)
·
OSTI ID:7057667
Seven-methylguanine adducts in DNA are normally present at high levels and increase on aging: Analysis by HPLC with electrochemical detection
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Sat Oct 01 00:00:00 EDT 1988
· Proceedings of the National Academy of Sciences of the United States of America; (USA)
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OSTI ID:5608096
Composition and characterization of tRNA from Methanococcus vannielii
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Sat Dec 31 23:00:00 EST 1977
· J. Bacteriol.; (United States)
·
OSTI ID:7287105
Related Subjects
560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
AMINES
ANIMAL TISSUES
ANIMALS
AROMATICS
AZAARENES
BIOLOGICAL ACCUMULATION
BIOLOGICAL EFFECTS
BLADDER
BODY
CARCINOGENESIS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DNA
DNA ADDUCTS
EPITHELIUM
GUANINE
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
KINETICS
MAGNETIC RESONANCE
MAMMALS
MASS SPECTROSCOPY
METHYLATION
MUTAGENESIS
NITROSO COMPOUNDS
NITROSOUREAS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PATHOGENESIS
PURINES
RATS
RESONANCE
RODENTS
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
TISSUES
URINARY TRACT
VERTEBRATES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
AMINES
ANIMAL TISSUES
ANIMALS
AROMATICS
AZAARENES
BIOLOGICAL ACCUMULATION
BIOLOGICAL EFFECTS
BLADDER
BODY
CARCINOGENESIS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DNA
DNA ADDUCTS
EPITHELIUM
GUANINE
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
KINETICS
MAGNETIC RESONANCE
MAMMALS
MASS SPECTROSCOPY
METHYLATION
MUTAGENESIS
NITROSO COMPOUNDS
NITROSOUREAS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PATHOGENESIS
PURINES
RATS
RESONANCE
RODENTS
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
TISSUES
URINARY TRACT
VERTEBRATES