The Chemical Interplay between Nitric Oxide and Mitochondrial Cytochrome c Oxidase: Reactions, Effectors and Pathophysiology
Figure 1
Dual-pathway model for the interaction of NO with mitochondrial cytochrome oxidase. The nature of the interaction between NO and CcOX depends on the catalytic intermediates targeted, and these are differently populated at different concentrations of O2 and reduced cytochrome c. The oxidized intermediates O, P, F (see text) are overall more populated with increasing O2 availability, and/or decreasing the concentration of reduced cytochrome c in the mitochondrion: these intermediates react with NO generating a nitrite-inhibited CcOX. The reduced species E and R (see text) buildup, instead, upon decreasing O2 and/or increasing the concentration of reduced cytochrome c: upon reacting with NO, these intermediates generate a heme -NO complex, in competition with oxygen.
