DNA Base and Deoxyribose Modification by the Carbon-Centered Radical Generated from 4-(Hydroxymethyl)benzenediazonium Salt, a Carcinogen in Mushroom
摘要:
Modification of the base and the sugar moieties of DNA with 4-(hydroxymethyl)benzenediazonium salt (HMBD), a carcinogen in the mushroom Agaricus bisporus, was investigated. When deoxyribonucleosides dGuo, dAdo, dThd, and dCyd were incubated with HMBD at pH 7.4 and 37 degrees C, the levels of all the nucleosides were decreased. The decrease was inhibited by ethanol or Cys. When deoxyribose was incubated with HMBD, malonaldehyde was released as assessed by the thiobarbituric acid reactivity. The release was inhibited by ethanol. Major products of the reaction of dGuo and dAdo with HMBD were isolated, and their structures were established to be 8-[4-(hydroxymethyl)phenyl]dGuo (8-HMP-dGuo) and 8-[4-(hydroxymethyl)phenyl]dAdo (8-HMP-dAdo), respectively. Calf thymus DNA treated with HMBD was enzymatically digested into nucleosides, in which 8-HMP-dGuo and 8-HMP-dAdo were detected. Formation of the modified nucleosides in DNA was inhibited by ethanol or 2-mercaptoethanol. Malonaldehyde was released from DNA treated with HMBD, which indicated that the deoxyribose moiety of DNA had been damaged. The results indicate that the 4-(hydroxymethyl)phenyl radical generated from HMBD can directly modify the base and the sugar moieties of DNA under the mild conditions. Inhibitory effect of ethanol was ascribable to its scavenging activity for the carbon-centered radical. The inhibitory effect of Cys and 2-mercaptoethanol was found to be due to the formation of the reversible adducts between HMBD and the SH compounds.
Efficient One-Step Suzuki Arylation of Unprotected Halonucleosides, Using Water-Soluble Palladium Catalysts
作者:Elizabeth C. Western、Jonathan R. Daft、Edward M. Johnson、Peter M. Gannett、Kevin H. Shaughnessy
DOI:10.1021/jo034289p
日期:2003.8.1
modification of unprotectedhalonucleosides is reported herein. Using a catalyst derived from tris(3-sulfonatophenyl)phosphine (TPPTS) and palladium acetate, 8-bromo-2'-deoxyguanosine (8-BrdG) is coupled with arylboronic acids to give 8-aryl-2'-deoxyguanosine adducts (8-ArdG) in excellent yield in a 2:1 water:acetonitrile solvent mixture. The TPPTS ligand was found to be superior to water-soluble alkylphosphines
Different Patterns of Mutagenicity of Arenediazonium Ions in V79 Cells and Salmonella typhimurium TA102: Evidence for Different Mechanisms of Action
作者:Terence Lawson、Peter M. Gannett、Wai-Ming Yau、Nar S. Dalal、Bela Toth
DOI:10.1021/jf00058a014
日期:1995.10
The edible mushroom Agaricus bisporus contains several arylhydrazines and arenediazonium ions that are genotoxins. The mechanism whereby arylhydrazines and arenediazonium ions are genotoxic is unknown and may be due to the arenediazonium ion itself or to aryl radicals. The reactions of four arenediazonium ions (p-X-C6H5N2+, X = -CH3, -CH2OH, -CH2OCH3, -CO2H) with purine bases, their mutagenicity, their ability to cause DNA damage, and their tendency toward free radical formation have been studied to elucidate the genotoxic species. It is suggested that either the arenediazonium or aryl radical can act as the ultimate genotoxin. Which species is dominant is dependent upon the arenediazonium ion reduction potential. This relationship may be useful in designing future studies of arenediazonium ion genotoxicity.
DNA Base and Deoxyribose Modification by the Carbon-Centered Radical Generated from 4-(Hydroxymethyl)benzenediazonium Salt, a Carcinogen in Mushroom
Modification of the base and the sugar moieties of DNA with 4-(hydroxymethyl)benzenediazonium salt (HMBD), a carcinogen in the mushroom Agaricus bisporus, was investigated. When deoxyribonucleosides dGuo, dAdo, dThd, and dCyd were incubated with HMBD at pH 7.4 and 37 degrees C, the levels of all the nucleosides were decreased. The decrease was inhibited by ethanol or Cys. When deoxyribose was incubated with HMBD, malonaldehyde was released as assessed by the thiobarbituric acid reactivity. The release was inhibited by ethanol. Major products of the reaction of dGuo and dAdo with HMBD were isolated, and their structures were established to be 8-[4-(hydroxymethyl)phenyl]dGuo (8-HMP-dGuo) and 8-[4-(hydroxymethyl)phenyl]dAdo (8-HMP-dAdo), respectively. Calf thymus DNA treated with HMBD was enzymatically digested into nucleosides, in which 8-HMP-dGuo and 8-HMP-dAdo were detected. Formation of the modified nucleosides in DNA was inhibited by ethanol or 2-mercaptoethanol. Malonaldehyde was released from DNA treated with HMBD, which indicated that the deoxyribose moiety of DNA had been damaged. The results indicate that the 4-(hydroxymethyl)phenyl radical generated from HMBD can directly modify the base and the sugar moieties of DNA under the mild conditions. Inhibitory effect of ethanol was ascribable to its scavenging activity for the carbon-centered radical. The inhibitory effect of Cys and 2-mercaptoethanol was found to be due to the formation of the reversible adducts between HMBD and the SH compounds.