Document Detail

Evidence for an electrogenic 3-deoxy-2-oxo-D-gluconate--proton co-transport driven by the protonmotive force in Escherichia coli K12.
MedLine Citation:
PMID:  23116     Owner:  NLM     Status:  MEDLINE    
Evidence is presented indicating that the carrier-mediated uptake of 3-deoxy-2-oxo-D-gluconate and D-glucuronate in Escherichia coli K12 is driven by the deltapH and deltapsi components of the protonmotive force. 1. Approximately two protons enter the cells with each sugar molecule, independent of the sugar and the strain used. 2. In respiring cells, the magnitude of the pH gradient alone, as measured by distribution of [3H]acetate, appears to be insufficient to account for the chemical gradient of 3-deoxy-2-oxo-D-gluconate that is developed between pH 6.0 and 8.0. 3. If the external pH is varied between 5.5 and 8.0, 3-deoxy-2-oxo-D-gluconate uptake is gradually inhibited by valinomycin plus K+ ions, whereas the inhibition caused by nigericin is concomitantly relieved, thus reflecting the relative contribution of deltapH and deltapsi to the total protonmotive force at each external pH. 4. 3-Deoxy-2-oxo-D-gluconate can be transiently accumulated into isolated membrane vesicles in response to an artificially induced pH gradient. The process is stimulated when the membrane potential is collapsed by valinomycin in the presence of K+ ions.
A Lagarde
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Biochemical journal     Volume:  168     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1977 Nov 
Date Detail:
Created Date:  1978-02-23     Completed Date:  1978-02-23     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  211-21     Citation Subset:  IM    
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MeSH Terms
Biological Transport, Active
Cations / metabolism
Cell Membrane / metabolism
Escherichia coli / drug effects,  metabolism*
Gluconates / metabolism*
Hydrogen-Ion Concentration
Ionophores / pharmacology
Potassium / metabolism
Reg. No./Substance:
0/Cations; 0/Gluconates; 0/Ionophores; 0/Protons; 7440-09-7/Potassium

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

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