Linked Life Data

14502423

Source:http://linkedlifedata.com/resource/pubmed/id/14502423

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-9-22
pubmed:abstractText
ASCT1 is a member of the glutamate transporter superfamily cloned from human brain and characterized as a Na(+)-dependent neutral amino-acid exchanger, which displays substrate-induced chloride-channel activity and mediates concentrative transport of alanine. Initial studies in ASCT1-expressing Xenopus laevis oocytes showed that proline did not elicit measurable currents, in contrast to what occurred with alanine, serine or cysteine, suggesting that proline was not an ASCT1 substrate, although it induced the release of alanine from preloaded oocytes. Here, we have studied the uptake of proline and hydroxyproline by ASCT1-expressing oocytes in order to investigate the ability of ASCT1 to translocate these imino acids. The results demonstrate ASCT1-mediated proline transport that is Na(+)-dependent, saturable, inhibited by the reported ASCT1 substrates as well as by hydroxyproline and can drive the imino acid against its concentration gradient. The apparent kinetic constants for the transport of alanine and the imino acids, obtained with oocytes from the same batch, showed maximal transport rate for proline and hydroxyproline to be half of that for alanine. However, K(0.5) for proline was 704 +/- 86 microM, about three times higher than alanine K(0.5) (203.3 +/- 36.4 microM), whereas hydroxyproline K(0.5) was 33.2 +/- 4.3 microM, indicating that the hydroxylation on carbon 4 of proline strongly increases the affinity of ASCT1 for this proline derivative. In summary, the present work demonstrates for the first time the ability of ASCT1 to transport proline and hydroxyproline.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-2631
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
195
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27-32
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Transport of proline and hydroxyproline by the neutral amino-acid exchanger ASCT1.
pubmed:affiliation
Departamento de Fisiología y Nutrición, Universidad de Navarra, 31080 Pamplona, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't