:NO Mitochondrial Respiration?
How Nitric Oxide Inhibits Cytochrome c Oxidase
Background
What's New?
Figure 1: Cytochrome c Oxidase in the inner mitochronrial membrane. ShelaghFerguson-Miller
Nitric oxide (:NO) is a physiological signaling molecule that plays a significant role in regulating mitochondrial respiration. Nitric oxide prevents oxygen consumption by inhibiting the enzyme cytochrome c oxidase (CCO), the terminal electron acceptor in the mitochondrial electron transport chain. Why is this a problem?
Relation to Sepsis: Patients who develop potentially fatal septic infections experience increased cellular NO concentrations. Some NO synthase enzymes are induced, causing elevated NO concentrations that are associated with mitochondrial dysfunction and subsequent mortality.
Discoveries by Mason et. al (2006) provide new insights that describe the molecular interactions between nitric oxide, oxygen and cytochrome c oxidase. These results lead to a better understanding of the pathology of and possible treatments for sepsis.