The reaction of Escherichia coli cytochrome bo with H202: Evidence for the formation of an oxyferryl species by two distinct routes

FEBS Letters

Brittain, Thomas¹  Watmough, Nicholas J.¹  Little, Richard H.¹  Greenwood, Colin¹ 

[1] Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ UK

关键词: Escherichia coli;    Cytochrome bo;    Quinol oxidase;    Hydrogen peroxide;    Oxyferryl heme;   

DOI  :  10.1016/S0014-5793(96)01253-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have re-examined the reaction of fast oxidised cytochrome bo with H₂O₂ in a stopped-flow spectrophotometer. Monitoring the reaction at 582 nm allows us to observe the formation and decay of a spectroscopically distinct intermediate which accumulates transiently prior to the formation of an oxyferryl species previously characterised in this laboratory (Watmough, N.J., Cheesman, M.R., Greenwood, C. and Thomson, A.J. (1994) Biochem. J. 300, 469–475 [1]). The reaction shows three distinct phases of which the fast and intermediate phases are bimolecular and show a marked pH dependence. Initially these results appeared incompatible with the report that only one equivalent of H₂O₂ is required to generate the oxyferryl species (Moody, A.J. and Rich, P.R. (1994) Eur. J. Biochem. 226, 731–737 [2]). However, these data can be reconciled by a branched reaction mechanism whose contributions differ according to the peroxide concentration used.

【 授权许可】

Unknown