Amino Acids

, Volume 32, Issue 4, pp 535–542 | Cite as

EPR spin-trapping of protein radicals to investigate biological oxidative mechanisms

  • O. Augusto
  • S. Muntz Vaz
Review Article


Presently, free radicals and oxidants are considered to mediate from signaling circuits involved in physiology and pathology to cell and tissue injury. The elucidation of these many inter-related processes requires a better understanding of cellular oxidative mechanisms many of which are mediated by protein radicals. Here, we will discuss the potentialities of EPR spin-trapping of protein radicals to unravel oxidative mechanisms. An overview of the methodology and its application to identify protein residues that are the target of specific oxidants, characterize emerging oxidants, and discriminate radical from non radical mechanisms will be presented. The examples are based on work developed in our laboratories but will be discussed in a broad scenario to emphasize that simple experiments can provide relevant insights into the biological reactivity of known and emerging biological oxidants and into signaling mechanisms.

Keywords: Oxidative mechanisms – Protein radicals – EPR – EPR spin-trapping 



bovine serum albumin


superoxide dismutase


3,5-dibromo-4-nitrosobenzenesulfonic acid


5,5-dimethylpyrroline N-oxide


electron paramagnetic resonance


electrospray ionization






peroxycarbonate or peroxymonocarbonate


human serum albumin


liquid chromatography


matrix-assisted laser desorption/ionization time of flight




mass spectrometry




sum of peroxynitrite anion (ONOO, oxoperoxonitrate (−1)) and peroxynitrous acid (ONOOH, hydrogen oxoperoxonitrate) unless specified


reactive nitrogen species


reactive oxygen species


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • O. Augusto
    • 1
  • S. Muntz Vaz
    • 1
  1. 1.Departamento de Bioquímica, Instituto de QuímicaUniversidade de São PauloSão PauloBrazil

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