Pathophysiological functions of nitric oxide-mediated protein modifications

Specific post-translational modifications resulting from the reaction of nitric oxide or nitric oxide-derived reactive nitrogen species with selective proteins may explain the pleiotropic effects of this molecule in biological systems. Three specific reactions, binding to metal centers, nitrosation of nucleophilic centers and nitration of aromatic residues constitute a major component of the biological reactivity of nitric oxide. We postulate that the chemical reactivity of nitric oxide within biological systems allows this simple diatomic molecule to operate as an integrator of physiological homeostasis and potentially under not completely understood circumstances as a mediator of pathological phenotypes. This chapter reviews the chemistry, putative biological functions and significance of the principal nitric oxide-mediated proteins modifications.