Diffusion of peroxynitrite, its precursors, and derived reactive species, and the effect of cell membranes

Peroxynitrite is a powerful oxidant formed in vivo in sites where superoxide and nitric oxide coincide. Peroxynitrite is cytotoxic through oxidative modification of target biomolecules that can occur by direct or indirect reactions. Indirect reactions usually involve the generation of peroxynitrite-derived radicals that include nitrogen dioxide, hydroxyl radical, and carbonate radical. All these species have different behaviors in vivo, because of their intrinsic reactivity and how effectively they can be compartmentalized by cellular membranes. In this review, we analyze quantitative information on the estimated half-lives and the corresponding estimated diffusion distances of peroxynitrite, its precursors, and its derived reactive species in vivo. Furthermore, we discuss the permeability of cellular and synthetic lipid membranes to the different species and how effective compartmentalization is achieved for some of them, limiting the biological site of reactions.