Linked Life Data

6725262

Source:http://linkedlifedata.com/resource/pubmed/id/6725262

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1984-7-2
pubmed:abstractText
Brush-border membranes of renal proximal tubules were solubilized with deoxycholate and some proteins were separated and incorporated into proteoliposomes by a reconstitution procedure which was analyzed in detail. The proteoliposomes contained mainly polypeptides with molecular weights of 152,000, 94,000, and 52,000, each of which could be separated further into homologous polypeptides with different isoelectric points. In the proteoliposomes, Na+ cotransport systems for D-glucose, acidic and neutral amino acids, and mono- and dicarboxylic acids were demonstrated by showing that due to an inwardly directed Na+ gradient the substrate concentrations in the proteoliposomes increased significantly over their respective equilibrium values. Using inhibition experiments, selectivity of the different transporters could be demonstrated. Studying the reconstituted L-glutamate transporter in detail, countertransport of L-glutamate and K+ was shown (i) at Na+ equilibrium the intraliposomal L-glutamate concentration increased significantly over the equilibrium value if an outside-directed K+ gradient was applied; (ii) Rb+ influx was significantly stimulated by the outflux of L-glutamate. By applying a K+ diffusion potential across the liposomal membrane by addition of valinomycin it could be shown that during L-glutamate transport in the presence of Na+ and K+ positive charge is transferred together with L-glutamate and Na+. The apparent Km value of L-glutamate uptake driven by concentration differences of 89 mM Na+ (out greater than in) and 89 mM K+ (in greater than out) was 26.3 +/- 1.3 microM. The Vmax value of 70.2 +/- 2.3 pmol X mg of protein-1 X S-1 was half the value measured in intact membranes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
259
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6548-58
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Reconstitution and partial purification of several Na+ cotransport systems from renal brush-border membranes. Properties of the L-glutamate transporter in proteoliposomes.
pubmed:publicationType
Journal Article