In Vitro DNA Deamination by -Nitrosaminoaldehydes Determined by GC/MS-SIM Quantitation
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- 作者：Misun Park and Richard N. Loeppky
- 刊名：Chemical Research in Toxicology
- 出版年：2000
- 出版时间：February 2000
- 年：2000
- 卷：13
- 期：2
- 页码：72 - 81
- 全文大小：224K
- 年卷期：v.13,no.2(February 2000)
- ISSN：1520-5010
文摘
The deamination of DNA bases by three 
-nitrosaminoaldehydes, butylethanalnitrosamine,methylethanalnitrosamine, and N-nitroso-2-hydroxymorpholine (NHMOR), the direct metabolite of potent animal carcinogen N-nitrosodiethanolamine, was demonstrated by a set of invitro experiments. The deamination of guanine, adenine, and cytosine bases in nucleotides,oligonucleotides, and calf thymus DNA gave xanthine, hypoxanthine, and uracil, respectively.The order of relative reactivities of the bases was as listed above. Deamination of cytosine touracil was detected by the reaction of 32P-labeled oligonucleotide ([5'-32P]CGAT) followed byenzymatic hydrolysis. Quantitative analysis of deamination of guanine and adenine in calfthymus DNA was performed by a gas chromatography/mass spectrometry-selected ionmonitoring method. Both the extent and the rate of the deamination reactions which occur bytransnitrosation from the -nitrosaminoaldehyde to the base were determined for formationof xanthine and hypoxanthine. The deamination of guanine by NHMOR remained significantat low substrate levels.
-nitrosaminoaldehydes, butylethanalnitrosamine,methylethanalnitrosamine, and N-nitroso-2-hydroxymorpholine (NHMOR), the direct metabolite of potent animal carcinogen N-nitrosodiethanolamine, was demonstrated by a set of invitro experiments. The deamination of guanine, adenine, and cytosine bases in nucleotides,oligonucleotides, and calf thymus DNA gave xanthine, hypoxanthine, and uracil, respectively.The order of relative reactivities of the bases was as listed above. Deamination of cytosine touracil was detected by the reaction of 32P-labeled oligonucleotide ([5'-32P]CGAT) followed byenzymatic hydrolysis. Quantitative analysis of deamination of guanine and adenine in calfthymus DNA was performed by a gas chromatography/mass spectrometry-selected ionmonitoring method. Both the extent and the rate of the deamination reactions which occur bytransnitrosation from the -nitrosaminoaldehyde to the base were determined for formationof xanthine and hypoxanthine. The deamination of guanine by NHMOR remained significantat low substrate levels.