Peroxynitrite Formation and Detection in Living Cells

Abstract Different cell types produce peroxynitrite under conditions of simultaneous generation of its precursor radicals, superoxide and nitric oxide. The detection of cell-derived peroxynitrite is technically challenging due to its short biological half-life and low steady-state concentration and the shortage of specific methods. However, appropriate use of molecular footprints and probes together with a wise application of pharmacological and genetic approaches, allow for its unambiguous detection. Among the molecular footprints left by peroxynitrite, the measurement and identification of tyrosine-nitrated proteins is of prime relevance. Regarding molecular probes, recent advances on the characterization of the reactivity of boronate-based molecules with peroxynitrite have opened new and more specific ways for cellular detection. A critical analysis of the chemical basis and usefulness of the existing methods utilized for the cellular detection of peroxynitrite will be performed. Also, the role of intracellular modulators of peroxynitrite reactivity and levels (e.g . , CO 2 , uric acid, peroxiredoxins) and how they can influence the detected levels will be assessed. The accurate cellular detection of peroxynitrite in different cellular and extracellular compartments and the estimation of its formation rates, represent fundamental steps to understand how nitric oxide-derived oxidants affect biological processes, including mitochondrial dysfunction and cell death.