Cytochrome bd oxygen reductase from Escherichia coli has three hemes, b558, b595 and d. We found that the enzyme, as-prepared or in turnover with O2, rapidly decomposes H2O2 with formation of approximately half a mole of O2 per mole of H 2O2. Such catalase activity vanishes upon cytochrome bd reduction, does not compete with the oxygen-reductase activity, is insensitive to NO, CO, antimycin-A and N-ethylmaleimide (NEM), but is inhibited by cyanide (Ki ∼2.5 μM) and azide. The activity, possibly associated with heme-b595, was also observed in catalase-deficient E. coli cells following cytochrome bd over-expression suggesting a protective role against oxidative stress in vivo. © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Borisov, V. B., Forte, E., Davletshin, A., Mastronicola, D., Sarti, P., & Giuffrè, A. (2013). Cytochrome bd oxidase from Escherichia coli displays high catalase activity: An additional defense against oxidative stress. FEBS Letters, 587(14), 2214–2218. https://doi.org/10.1016/j.febslet.2013.05.047