Document Detail

Lysine uptake and exchange in Corynebacterium glutamicum.
MedLine Citation:
PMID:  2123868     Owner:  NLM     Status:  MEDLINE    
Resting cells of Corynebacterium glutamicum (ATCC 13032) accumulate [14C]lysine by a transport system with a relatively high affinity (10 microMs) and a low maximum velocity (0.15 nmol/min per mg [dry weight]). Uptake of lysine was not inhibited by uncouplers or by ionophores affecting the ion gradients and the energetic state of the cell. Analysis of intracellular amino acid concentrations during the transport reaction as well as kinetic studies revealed that the observed uptake of lysine in fact represents a homologous antiport between extracellular [14C]lysine and intracellular unlabeled lysine. Intracellular [14C]lysine could only be released by the addition of unlabeled lysine to the bacterial suspension. In contrast to this homologous antiport reaction, we observed net uptake of lysine in lysine-depleted cells of a lysine auxotrophic strain. This net uptake was found to be electrogenic and could also be observed as a heterologous antiport reaction in wild-type cells under particular conditions. In this case exchange was mediated between internal lysine and external alanine, isoleucine, or valine. This antiport was electrogenic, since the substrates differ in charge. The cells can switch between electroneutral homologous exchange and electrogenic heterologous antiport mode during fermentation because of changing metabolic conditions.
S Bröer; R Krämer
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bacteriology     Volume:  172     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  1990 Dec 
Date Detail:
Created Date:  1991-01-24     Completed Date:  1991-01-24     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  7241-8     Citation Subset:  IM    
Institut für Biotechnologie I, Forschungszentrum Jülich, Federal Republic of Germany.
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MeSH Terms
Biological Transport, Active / drug effects
Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
Corynebacterium / metabolism*
Cytoplasm / metabolism
Hydrogen-Ion Concentration
Lysine / metabolism*
Membrane Potentials / drug effects
Valinomycin / pharmacology
Reg. No./Substance:
2001-95-8/Valinomycin; 555-60-2/Carbonyl Cyanide m-Chlorophenyl Hydrazone; 56-87-1/Lysine

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

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