Electrogenic Reactions of Cytochrome bd

Cytochrome bd is one of the two terminal quinol oxidases in the respiratory chain of Escherichia coli. The enzyme catalyzes charge separation across the bacterial membrane during the oxidation of quinols by dioxygen but does not pump protons. In this work, the reaction of cytochrome bd with O2 and r...

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Bibliographic Details
Published in:Biochemistry (Easton) 2000-11, Vol.39 (45), p.13800-13809
Main Authors: Jasaitis, Audrius, Borisov, Vitaliy B, Belevich, Nikolai P, Morgan, Joel E, Konstantinov, Alexander A, Verkhovsky, Michael I
Format: Article
Language:English
Subjects:
Carbon Monoxide - chemistry
Cytochromes - chemistry
electrometrometry
Electron Transport
Electron Transport Chain Complex Proteins
Escherichia coli
Escherichia coli - enzymology
Escherichia coli Proteins
Hydrogen Peroxide - chemistry
Membrane Potentials
Oxidation-Reduction
Oxidoreductases - chemistry
Oxygen - chemistry
Photolysis
Spectrophotometry
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Summary:Cytochrome bd is one of the two terminal quinol oxidases in the respiratory chain of Escherichia coli. The enzyme catalyzes charge separation across the bacterial membrane during the oxidation of quinols by dioxygen but does not pump protons. In this work, the reaction of cytochrome bd with O2 and related reactions has been studied by time-resolved spectrophotometric and electrometric methods. Oxidation of the fully reduced enzyme by oxygen is accompanied by rapid generation of membrane potential (ΔΨ, negative inside the vesicles) that can be described by a two-step sequence of (i) an initial oxygen concentration-dependent, electrically silent, process (lag phase) corresponding to the formation of a ferrous oxy compound of heme d and (ii) a subsequent monoexponential electrogenic phase with a time constant
ISSN:0006-2960
1520-4995
DOI:10.1021/bi001165n