[35] Assessment of peroxynitrite scavengers in Vitro

Abstract

Publisher Summary This chapter discusses various methods that help in evaluating the effects of different fluxes of nitric oxide on iron or hemoprotein-mediated oxidation. Nitric oxide (NO) may enhance or inhibit oxidative reactions depending on the relative fluxes of O 2- , H 2 O 2 , and NO as well as the concentration of the metal catalyst. For example, within the intracellular space—where superoxide dismutase (SOD) is present in relatively high concentrations—the interaction between NO and O 2- is expected to be diminished. NO may play a critical role in inhibiting hemoprotein-catalyzed oxidation reactions by either preventing the interaction of H 2 O 2 with the iron chelate and/or the hemoprotein or by reducing the ferryl derivatives to their corresponding met forms. However, in the extracellular environment where hemoproteins such as myoglobin (Mb) and haemoglobin (Hb) may be released in high concentrations during times of traumatic injury or inflammation and concentrations of SOD are low, NO may enhance or inhibit O 2 -dependent oxidative reactions depending on the relative fluxes of each radical.