Document Detail


Mechanism and Regulation of Isoleucine Excretion in Corynebacterium glutamicum.
MedLine Citation:
PMID:  16535397     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Whole cells of Corynebacterium glutamicum were loaded with high cytoplasmic l-isoleucine concentrations, and isoleucine excretion from these cells was studied in terms of mechanism and regulation. The transmembrane isoleucine flux could be differentiated into carrier-mediated uptake, carrier-mediated excretion, and diffusion. After discrimination from the other transmembrane solute movements, the outward-directed flux, which was due to the activity of the isoleucine excretion carrier, was characterized with respect to its energy dependence and its regulation at the level of expression. Isoleucine excretion was shown to function as a secondary transport process, driven by the membrane potential and coupled to the movement of protons, presumably with a stoichiometry of 2:1 (H(sup+)/isoleucine). Of a variety of putative transport substrates, only leucine was able to compete for isoleucine at the cis (cytosolic) side of the export carrier. Cytoplasmic isoleucine concentrations higher than 20 mM induce the activity of the isoleucine excretion system. This effect is specific for isoleucine and is inhibited by the presence of chloramphenicol. Apart from leucine, other amino acids and related amino acid analogs are not able to induce isoleucine excretion. The complex pattern of regulation of the isoleucine excretion system at the level of activity and expression is shown to be related to the pattern of regulation of the isoleucine uptake system in C. glutamicum in terms of physiological significance.
Authors:
T Hermann; R Kramer
Related Documents :
5225727 - Urinary amino acid excretion in subjects with leukaemia.
1855627 - Bis(2-methoxyethyl) ether: metabolism and embryonic disposition of a developmental toxi...
2386057 - Selective effect of mineralocorticoid replacement therapy on renal acid excretion in co...
10711787 - Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine and 5-(hydroxymethyl) uracil in smokers.
5225727 - Urinary amino acid excretion in subjects with leukaemia.
18831967 - Keeping an eye on retinoic acid signaling during eye development.
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  62     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  1996 Sep 
Date Detail:
Created Date:  2010-06-25     Completed Date:  2010-06-25     Revised Date:  2010-09-15    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3238-44     Citation Subset:  -    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Comments/Corrections

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


Previous Document:  Long-Term Continuous Cultivation of Clostridium beijerinckii in a Two-Stage Chemostat with On-Line S...
Next Document:  Atropine Metabolism by Pseudomonas sp. Strain AT3: Evidence for Nortropine as an Intermediate in Tro...