Document Detail


Oxygenated Cytochrome o. An active intermediate observed in whole cells of Vitreoscilla.
MedLine Citation:
PMID:  845146     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The oxygenerated form of cytochrome o can be readily observed in whole cell suspensions of Vitreoscilla because it is the predominant steady state form of the cytochrome in respiring cells. When oxygen is introduced to an anaerobic suspension of cells, the steady state is established immediately and absorption maxima are observed at 578, 545, and 425 nm in difference spectra using ammonium persulfate-oxidized cells as reference. The oxygenerated form of cytochrome o is identified as the predominant steady state species during turnover of the cytochrome in vivo from the close coincidence of these spectra with those obtained using purified cytochrome. When the dissolved oxygen is consumed, the spectrum of the oxygenated form is replaced by the spectrum of the reduced form. Glutamate increased the respiration of these cells and decreased the duration of the steady state. Spectra of the oxygenated form of cytochrome o could also be obtained by using starved cells as reference, i.e. (untreated cells) - (starved cells) difference spectra. These results implicate the oxygenated form of cytochrome o as an active intermediate in terminal electron transport of these cells. In the presence of 1 mM cyanide, which inhibits the respiration of Vitreoscilla, the duration of the steady state was increased and the steady state spectrum was altered, showing that turnover of the cytochrome was inhibitied and formation of the oxygenated form wsa decreased. All these results suggest that the cyclic changes of cytochrome o in terminal respiration involve the oxidized, reduced, and oxygenated forms.
Authors:
D A Webster; Y Orii
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  252     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1977 Mar 
Date Detail:
Created Date:  1977-05-20     Completed Date:  1977-05-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1834-6     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Bacteria / metabolism*
Cytochromes* / metabolism
Oxidation-Reduction
Oxygen Consumption
Spectrophotometry
Chemical
Reg. No./Substance:
0/Cytochromes

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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