Linked Life Data

9092712

Source:http://linkedlifedata.com/resource/pubmed/id/9092712

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-4-29
pubmed:abstractText
The mechanism by which H+ alters the kinetics of the H+-coupled peptide transporters PEPT 1 and PEPT 2 was investigated in two different cell lines which differentially express these transporters, namely Caco-2 cells (PEPT 1) and SKPT cells (PEPT 2). The effects of H+ on the affinity and the maximal velocity of Gly-Sar uptake were analyzed in these cells under identical conditions. In both cells, H+ influenced only the maximal velocity of uptake and not the apparent affinity. The effects of H+ on the IC50 values (i.e., concentration necessary to cause 50% inhibition) of the cationic dipeptide Ala-Lys and the anionic dipeptide Ala-Asp for inhibition of Gly-Sar uptake were also investigated. H+ did not change the IC50 value for Ala-Lys but did decrease the IC50 value for Ala-Asp considerably. The influence of diethylpyrocarbonate (DEP) on the kinetic parameters of PEPT 1 and PEPT 2 was then studied. Histidyl residues are the most likely amino acid residues involved in H+ binding and translocation in H+-coupled transport systems and DEP is known to chemically modify histidyl residues and block their function. DEP treatment altered the maximal velocity of Gly-Sar uptake but had no effect on its K(t) (Michaelis-Menten constant) or the IC50 values of Ala-Lys or Ala-Asp for the inhibition of Gly-Sar uptake. It is concluded that H+ stimulates PEPT 1 and PEPT 2 primarily by increasing the maximal velocity of the transporters with no detectable influence on the substrate affinity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Cephalexin, http://linkedlifedata.com/resource/pubmed/chemical/Diethyl Pyrocarbonate, http://linkedlifedata.com/resource/pubmed/chemical/Dipeptides, http://linkedlifedata.com/resource/pubmed/chemical/Histidine, http://linkedlifedata.com/resource/pubmed/chemical/PepT1 protein, http://linkedlifedata.com/resource/pubmed/chemical/Protons, http://linkedlifedata.com/resource/pubmed/chemical/SLC15A1 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Slc15a1 protein, rat, http://linkedlifedata.com/resource/pubmed/chemical/Symporters, http://linkedlifedata.com/resource/pubmed/chemical/alanylaspartic acid, http://linkedlifedata.com/resource/pubmed/chemical/glycylsarcosine, http://linkedlifedata.com/resource/pubmed/chemical/hydrogen-coupled oligopeptide...
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
1324
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
251-62
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Influence of proton and essential histidyl residues on the transport kinetics of the H+/peptide cotransport systems in intestine (PEPT 1) and kidney (PEPT 2).
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't