Reduction and destruction rates of nitroxide spin probes

Shimshon Belkin, Rolf J. Mehlhorn, K. Hideg, Olga Hankovsky, Lester Packer

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

A series of nitroxides was tested for rates of one-electron reduction in a chemical, a photochemical, and two biological systems by ESR assays. In all cases, piperidine and hydropyridine nitroxides were reduced consistently more rapidly than pyrroline and pyrrolidine nitroxides. Substituents on the nitroxides also affected reduction rates, although not as greatly as ring structure. One of the reduction systems, consisting of the photosensitizer FMN and the photoreductant EDTA, was used to study both anaerobic reduction and O2-dependent reoxidation of some of the nitroxides. Reduced piperidine and hydropyridine nitroxides were also oxidized more rapidly than the reduced pyrroline and pyrrolidine nitroxides. Reoxidation subsequent to reduction was partially inhibited by Superoxide dismutase, indicating that Superoxide radicals are involved in the process. Even after prolonged reoxidation, not all of the probe molecules were returned to their oxidized form, implying an irreversible "destruction" of the spin probe concomitant with its chemical reduction. Probe destruction was studied more specifically with a photochemical system for generating methyl radicals, which showed that these carboncentered radicals destroyed different nitroxides at rates which were much less influenced by the nitroxide structures than one-electron reduction was.

Original languageEnglish
Pages (from-to)232-243
Number of pages12
JournalArchives of Biochemistry and Biophysics
Volume256
Issue number1
DOIs
Publication statusPublished - 1987

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Electrons
Flavin Mononucleotide
Photosensitizing Agents
Edetic Acid
Superoxides
Superoxide Dismutase
Biological systems
pyrroline
pyrrolidine
piperidine
Paramagnetic resonance
Assays
Molecules
methyl radical

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Reduction and destruction rates of nitroxide spin probes. / Belkin, Shimshon; Mehlhorn, Rolf J.; Hideg, K.; Hankovsky, Olga; Packer, Lester.

In: Archives of Biochemistry and Biophysics, Vol. 256, No. 1, 1987, p. 232-243.

Research output: Contribution to journalArticle

Belkin, Shimshon ; Mehlhorn, Rolf J. ; Hideg, K. ; Hankovsky, Olga ; Packer, Lester. / Reduction and destruction rates of nitroxide spin probes. In: Archives of Biochemistry and Biophysics. 1987 ; Vol. 256, No. 1. pp. 232-243.
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