Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
10
|
| pubmed:dateCreated |
1996-6-20
|
| pubmed:abstractText |
The hPEPT1 cDNA cloned from human intestine (Liang, R., Fei, Y.-J., Prasad, P. D., Ramamoorthy, S., Han, H., Yang-Feng, T. L., Hediger, M. A., Ganapathy, V., and Leibach, F. H. (1995) J. Biol. Chem. 270, 6456-6463) encodes a H+/oligopeptide cotransporter. Using two-microelectrode voltage-clamp in Xenopus oocytes expressing hPEPT1, we have investigated the transport mechanisms of hPEPT1 with regard to voltage dependence, steady-state kinetics, and transient charge movements. The currents evoked by 20 mM glycyl-sarcosine (Gly-Sar) at pH 5.0 were dependent upon membrane potential (Vm) between -150 mV and +50 mV. Gly-Sar-evoked currents increased hyperbolically with increasing extracellular [H+], with Hill coefficient approximately 1, and the apparent affinity constant (K0.5H) for H+ was in the range of 0.05 1 microM. K0.5 for Gly-Sar (K0.5GS) was dependent upon Vm and pH; at -50 mV, K0.5H was minimal (approximately 0.7 mM) at pH 6.0. Following step-changes in Vm, in the absence of Gly-Sar, hPEPT1 exhibited H+-dependent transient currents with characteristics similar to those of Na+-coupled transporters. These charge movements (which relaxed with time constants of 2-10 ms) were fitted to Boltzmann relations with maximal charge (Qmax) of up to 12 nC; the apparent valence was determined to be approximately 1. Qmax is an index of the level of transporter expression which for hPEPT1 was in the order of 1011/oocyte. In general our data are consistent with an ordered, simultaneous transport model for hPEPT1 in which H+ binds first.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/DNA, Complementary,
http://linkedlifedata.com/resource/pubmed/chemical/Dipeptides,
http://linkedlifedata.com/resource/pubmed/chemical/Oligopeptides,
http://linkedlifedata.com/resource/pubmed/chemical/PepT1 protein,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/SLC15A1 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Symporters,
http://linkedlifedata.com/resource/pubmed/chemical/glycylsarcosine
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0021-9258
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
8
|
| pubmed:volume |
271
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
5430-7
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:8621398-Animals,
pubmed-meshheading:8621398-Carrier Proteins,
pubmed-meshheading:8621398-Cloning, Molecular,
pubmed-meshheading:8621398-DNA, Complementary,
pubmed-meshheading:8621398-Dipeptides,
pubmed-meshheading:8621398-Evoked Potentials,
pubmed-meshheading:8621398-Female,
pubmed-meshheading:8621398-Gene Expression,
pubmed-meshheading:8621398-Humans,
pubmed-meshheading:8621398-Hydrogen-Ion Concentration,
pubmed-meshheading:8621398-Intestines,
pubmed-meshheading:8621398-Kinetics,
pubmed-meshheading:8621398-Mathematics,
pubmed-meshheading:8621398-Membrane Potentials,
pubmed-meshheading:8621398-Models, Theoretical,
pubmed-meshheading:8621398-Oligopeptides,
pubmed-meshheading:8621398-Oocytes,
pubmed-meshheading:8621398-Patch-Clamp Techniques,
pubmed-meshheading:8621398-Recombinant Proteins,
pubmed-meshheading:8621398-Symporters,
pubmed-meshheading:8621398-Xenopus laevis
|
| pubmed:year |
1996
|
| pubmed:articleTitle |
Mechanisms of the human intestinal H+-coupled oligopeptide transporter hPEPT1.
|
| pubmed:affiliation |
Department of Physiology, UCLA School of Medicine, Los Angeles, California 90095-1751, USA.
|
| pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|