Alternative quinol oxidases AOX are membrane-bound enzymes capable of supporting cyanide- and antimycin A-resistant mitochondrial respiration. AOX 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 reduction of ATP production per oxygen consumed. 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
SUITbrowser question: AOX activity
- AOX activity can be measured with SUIT protocols: use the SUITbrowser to find your protocol.
|Dinant 2001 Curr Genet||Dinant M, Baurain D, Coosemans N, Joris B, Matagne RF (2001) Characterization of two genes encoding the mitochondrial alternative oxidase in Chlamydomonas reinhardtii. Curr Genet 39:101-8.||2001|
|BEC 2020.1 doi10.26124bec2020-0001.v1||Gnaiger E et al ― MitoEAGLE Task Group (2020) Mitochondrial physiology. https://doi.org/10.26124/bec:2020-0001.v1||2020|
|Kruessel 2014 Plant Physiol||Krüßel L, Junemann J, Wirtz M, Birke H, Thornton JD, Browning LW, Poschet G, Hell R, Balk J, Braun HP, Hildebrandt TM (2014) The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis. Plant Physiol 165:92-104.||2014|
|Welchen 2012 Biochim Biophys Acta||Welchen E, Hildebrandt TM, Lewejohann D, Gonzalez DH, Braun HP (2012) Lack of cytochrome c in Arabidopsis decreases stability of Complex IV and modifies redox metabolism without affecting Complexes I and III. Biochim Biophys Acta 1817:990-1001.||2012|
MitoPedia topics: Enzyme