ISSN:
1573-6881
Keywords:
Cytochrome oxidase
;
proton pumping
;
peroxidase
;
dioxygen reduction
;
catalytic cycle/time-resolved electrogenesis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Cytochrome oxidase (COX) is considered to integrate in a single enzyme two consecutive mechanistically different redox activities--oxidase and peroxidase--that can be catalyzed elesewhere by separate hemoproteins. From the viewpoint of energy transduction, the enzyme is essentially a proton pumping peroxidase with a built-in auxiliary eu-oxidase module that activates oxygen and prepares in situ H2O2, a thermodynamically efficient but potentially hazardous electron acceptor for the proton pumping peroxidase. The eu-oxidase and peroxidase phases of the catalytic cycle may be performed by different structural states of COX. Resolution of the proton pumping peroxidase activity of COX and identification of individual charge translocation steps inherent in this reaction are discussed, as well as the specific role of the two input proton channels in proton translocation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1020571930850
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