FEBS Letters 2013-07-11

Cytochrome bd oxidase from Escherichia coli displays high catalase activity: an additional defense against oxidative stress.

Vitaliy B Borisov, Elena Forte, Albert Davletshin, Daniela Mastronicola, Paolo Sarti, Alessandro Giuffrè

Index: FEBS Lett. 587(14) , 2214-8, (2013)

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Abstract

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 H2O2. 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 ~2.5μM) 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.Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.