The spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitrone stimulates peroxidase-mediated oxidation of deferoxamine. Implications for pharmacological use of spin-trapping agents

M. L. McCormick, G. R. Buettner, B. E. Britigan

Research output: Contribution to journalArticle

15 Scopus citations


The iron chelator deferoxamine (Desferal; DSFL) reacts with peroxidases and H2O2 to form the DSFL radical (DSFL.), which can be detected by EPR spectroscopy. We have found that DSFL· formation resulting from exposure to H2O2 and any of a number of different peroxidoses is greatly enhanced in the presence of the nitrone spin trap α-(4-pyridyl-1-oxide)-N-tert- butylnitrone (4-POBN). This enhancement was seen at 4-POBN concentrations as low as 200 μM. We observed a modest enhancement of DSFL· formation with 2- methyl-2-nitrosopropane. However, no enhancement was seen with 5,5-dimethyl- 1-pyrroline 1-oxide (DMPO) or phenyl-tert-butylnitrone. A modest enhancement was also seen with the nitrone compound pyridine N-oxide-2-Methyl-2- nitrosopropane and pyridine N-oxide were additionally capable of increasing enzymatic peroxidase activity as measured by o-dianisidine and/or tetramethylbenzidine oxidation. Furthermore, at high concentrations of 4- POBN (50 mM) in the absence of DSFL, we detected a peroxidase/H2O2- dependent 12-line EPR spectrum that likely represents a 4-POBN/·4-POBN nitrogen-centered spin adduct. In the presence of both 4-POBN (10 mM) and DMPO (100 mM), an 18-line EPR spectrum was observed consistent with formation of a DMPO/·4-POBN nitrogen-centered spin adduct. Thus, the nitrone spin trap 4-POBN can enhance the peroxidase-mediated formation of DSFL·, possibly via the formation of a transient 4-POBN radical species. These data suggest the importance of assessing the potential for nitrone spin traps to both inhibit and enhance biological oxidation prior to their use as potential pharmacological agents.

Original languageEnglish (US)
Pages (from-to)29265-29269
Number of pages5
JournalJournal of Biological Chemistry
Issue number49
Publication statusPublished - Jan 1 1995


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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