The alternative oxidase is a membrane-bound enzyme capable of supporting cyanide-and antimycin A-resistant mitochondrial respiration. It catalyzes the oxidation of ubiquinol and the reduction of oxygen to water in a four-electron process. As this bypasses several proton-translocating steps, induction of this alternative pathway is associated with a dramatic reduction of ATP production. AOX is found in most plants (including microalgae), many fungi and protists, but is not expressed in animals. AOX is inhibited by salicylhydroxamic acid (SHAM). Expression and activity of the enzyme are modified by environmental conditions such as temperature, oxidative stress, nutrient availability, and pathogens such as viruses.
Reference: Young 2013 Biochem Soc Trans
MitoPedia topics: Enzyme
SUITbrowser question: AOX activity
AOX activity can be measured with SUIT protocols: use the SUITbrowser to find your protocol.