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Electron transfer oxidation of DNA radicals by paranitroacetophenone

Abstract

The reaction of a typical electron-affinic sensitizer, paranitroacetophenone (PNAP) with the model compounds thymine, thymidine, thymidylic acid, deoxyribose and single and double-stranded DNA has been investigated by pulse radiolysis. Radicals formed by one-electron reduction of the bases and of DNA reacted rapidly and efficiently with PNAP by electron transfer. A small yield of transfer (< 10 per cent) was also observed arising from oxidation of the radicals formed by the small proportion of OH which reacted at the sugar moieties in DNA. In contrast, electron transfer oxidation by PNAP of radicals formed by the addition of OH to the base moieties, e.g. thymine, was not an efficient process. Further, addition of the sensitizer to the thymine OH-adduct proceeded at a rate that was too low to measure the pulse radiolysis. We conclude that, since the major sites of OH reaction by DNA are the heterocyclic bases (> 80 per cent), oxidation of the resultant radicals is unlikely to be a major step in the mechanism of sensitization by this typical hypoxic-cell sensitizer.
Authors:
Whillans, D W; Adams, G E [1] 
  1. Mount Vernon Hospital, Northwood (UK)
Publication Date:
Dec 01, 1975
Product Type:
Journal Article
Reference Number:
AIX-07-242146; EDB-76-093532
Resource Relation:
Journal Name: Int. J. Radiat. Biol.; (United Kingdom); Journal Volume: 28:6
Subject:
59 BASIC BIOLOGICAL SCIENCES; DNA; RADICALS; OXIDATION; ACETOPHENONE; AQUEOUS SOLUTIONS; CHEMICAL REACTION KINETICS; CHEMICAL REACTION YIELD; DEOXYRIBOSE; HYDRATION; HYDROXYL RADICALS; NITRO COMPOUNDS; RADIOLYSIS; RADIOSENSITIZERS; SOLVATED ELECTRONS; THYMIDINE; THYMIDYLIC ACID; THYMINE; TRANSIENTS; ALDEHYDES; AZINES; CARBOHYDRATES; CHEMICAL RADIATION EFFECTS; CHEMICAL REACTIONS; CHEMISTRY; DECOMPOSITION; DISPERSIONS; DRUGS; ELECTRONS; ELEMENTARY PARTICLES; FERMIONS; HETEROCYCLIC COMPOUNDS; HYDROXY COMPOUNDS; KETONES; KINETICS; LEPTONS; MIXTURES; MONOSACCHARIDES; NUCLEIC ACIDS; NUCLEOSIDES; NUCLEOTIDES; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PENTOSES; PYRIMIDINES; RADIATION CHEMISTRY; RADIATION EFFECTS; REACTION KINETICS; RESPONSE MODIFYING FACTORS; RIBOSIDES; SACCHARIDES; SOLUTIONS; SOLVATION; URACILS; YIELDS; 550200* - Biochemistry
OSTI ID:
7339234
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: IJRBA
Submitting Site:
INIS
Size:
Pages: 501-510
Announcement Date:

Citation Formats

Whillans, D W, and Adams, G E. Electron transfer oxidation of DNA radicals by paranitroacetophenone. United Kingdom: N. p., 1975. Web. doi:10.1080/09553007514551361.
Whillans, D W, & Adams, G E. Electron transfer oxidation of DNA radicals by paranitroacetophenone. United Kingdom. doi:10.1080/09553007514551361.
Whillans, D W, and Adams, G E. 1975. "Electron transfer oxidation of DNA radicals by paranitroacetophenone." United Kingdom. doi:10.1080/09553007514551361. https://www.osti.gov/servlets/purl/10.1080/09553007514551361.
@misc{etde_7339234,
title = {Electron transfer oxidation of DNA radicals by paranitroacetophenone}
author = {Whillans, D W, and Adams, G E}
abstractNote = {The reaction of a typical electron-affinic sensitizer, paranitroacetophenone (PNAP) with the model compounds thymine, thymidine, thymidylic acid, deoxyribose and single and double-stranded DNA has been investigated by pulse radiolysis. Radicals formed by one-electron reduction of the bases and of DNA reacted rapidly and efficiently with PNAP by electron transfer. A small yield of transfer (< 10 per cent) was also observed arising from oxidation of the radicals formed by the small proportion of OH which reacted at the sugar moieties in DNA. In contrast, electron transfer oxidation by PNAP of radicals formed by the addition of OH to the base moieties, e.g. thymine, was not an efficient process. Further, addition of the sensitizer to the thymine OH-adduct proceeded at a rate that was too low to measure the pulse radiolysis. We conclude that, since the major sites of OH reaction by DNA are the heterocyclic bases (> 80 per cent), oxidation of the resultant radicals is unlikely to be a major step in the mechanism of sensitization by this typical hypoxic-cell sensitizer.}
doi = {10.1080/09553007514551361}
journal = {Int. J. Radiat. Biol.; (United Kingdom)}
volume = {28:6}
journal type = {AC}
place = {United Kingdom}
year = {1975}
month = {Dec}
}