Independent generation and reactivity of 2-deoxy-5-methyleneuridin-5-yl, a significant reactive intermediate produced from thymidine as a result of oxidative stress

J Org Chem. 2000 Jul 28;65(15):4648-54. doi: 10.1021/jo000271s.

Abstract

2'-Deoxy-5-methyleneuridin-5-yl (1) is produced in a variety of DNA damage processes and is believed to result in the formation of lesions that are mutagenic and refractory to enzymatic repair. 2'-Deoxy-5-methyleneuridin-5-yl (1) was independently generated under anaerobic conditions via Norrish Type I photocleavage during Pyrex filtered photolysis of the benzyl ketone 7. The radical (1) exhibits behavior consistent with that of a resonance-stabilized radical. The KIE for hydrogen atom transfer from t-BuSH was found to be 7.3 +/- 1.7. Competition studies between radical recombination and hydrogen atom donors (2,5-dimethyltetrahydrofuran, kTrap = 46.1 +/- 15.4 M(-1) s(-1); propan-2-ol, kTrap = 13.6 +/- 3.5 M(-1) s(-1)) chosen to mimic the carbohydrate components of 2'-deoxyribonucleotides suggest that 2'-deoxy-5-methyleneuridin-5-yl (1) may be able to transfer damage from the nucleobase to the deoxyribose of an adjacent nucleotide in DNA under hypoxic conditions.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • DNA Damage / radiation effects
  • Deoxyribonucleotides / chemistry
  • Deoxyribonucleotides / metabolism
  • Deoxyribonucleotides / radiation effects
  • Deoxyribose / chemistry
  • Deoxyribose / metabolism
  • Deoxyribose / radiation effects
  • Free Radicals / chemistry*
  • Free Radicals / metabolism*
  • Free Radicals / radiation effects
  • Furans / metabolism
  • Hydrogen / metabolism
  • Kinetics
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Mercaptoethanol / metabolism
  • Oxidative Stress* / radiation effects
  • Oxygen / metabolism
  • Photolysis / radiation effects
  • Thymidine / chemistry*
  • Thymidine / metabolism
  • Thymidine / radiation effects*
  • Uridine / chemistry*
  • Uridine / metabolism*
  • Uridine / radiation effects

Substances

  • 2'-deoxy-5-methyleneuridin-5-yl
  • Deoxyribonucleotides
  • Free Radicals
  • Furans
  • 2,5-dimethyltetrahydrofuran
  • Deoxyribose
  • Mercaptoethanol
  • Hydrogen
  • Oxygen
  • Thymidine
  • Uridine