EB2003 SYMPOSIUM Mitochondrial Nitric Oxide A mitochondrial role for catabolism of nitric oxide in cardiomyocytes not involving oxymyoglobin

Peterson, Jim, Anthony J. Kanai, and Linda L. Pearce. A mitochondrial role for catabolism of nitric oxide in cardiomyocytes not involving oxymyoglobin. Am J Physiol Heart Circ Physiol 286: H55–H58, 2004; 10.1152/ajpheart.00744.2003.—The maximal concentration of nitric oxide (NO) developing in cultured cells following stimulation of endogenous NO synthases was shown to be submicromolar by NO-selective microelectrode measurements. In electron paramagnetic resonance experiments with isolated and finely divided pericardium, NO was found to react with oxymyoglobin to form metmyoglobin provided that NO was supplied at concentrations in excess of a few micromolar. However, at NO concentrations achievable by endogenous sources, this reaction did not take place to any measurable extent. Oxidative conversion of NO to nitrite ion by cytochrome c oxidase appears to be the most plausible route for cellular catabolism of NO.