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Published on: August 18, 2012
Detection of peroxynitrite in biological fluids
S Malcolm1, R Foust, C Hertkorn
1Stokes Research Institute and Department of Biochemistry and Biophysics, Children's Hospital of Philadelphia and The University of Pennsylvania, Philadelphia, PA.
Methods in Molecular Medicine
|February 23, 2011
Summary
Peroxynitrite (ONOO(-)) is a selective biological oxidant and nitrating agent. Its reactivity is influenced by reactions with CO(2) and protonation, impacting its dual role in biological systems.
Area of Science:
- Biochemistry
- Chemical Biology
- Oxidative Stress
Background:
- Peroxynitrite (ONOO(-)) functions as both a biological oxidant and nitrating agent.
- Unlike other oxidants, peroxynitrite exhibits selectivity towards biological targets.
- This selectivity is partly due to varying second-order rate constants (10^3–10^6 M⁻¹s⁻¹) for its reactions.
Purpose of the Study:
- To investigate the competing reaction pathways of peroxynitrite.
- To understand the influence of CO(2) and protonation on peroxynitrite's reactivity.
- To explore the implications of peroxynitrite's diffusion across membranes.
Main Methods:
- Analysis of peroxynitrite's reaction kinetics.
- Characterization of peroxynitrite's interaction with CO(2) and protonation.
- Assessment of peroxynitrite diffusion and reaction dynamics.
Main Results:
- Peroxynitrite's selectivity is modulated by its reaction rate constants with biological targets.
- Two competing pathways exist: protonation to peroxynitrous acid and reaction with CO(2).
- Peroxynitrite can diffuse through membranes, competing with its chemical transformations.
Conclusions:
- Peroxynitrite's biological effects are determined by a balance between diffusion and chemical reactions.
- The formation of the ONO(O)CO(2)(-) adduct enhances nitration but reduces oxidation.
- Membrane diffusion is a significant factor in peroxynitrite's biological activity.
