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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1993-9-15
|
| pubmed:abstractText |
The facilitative glucose transporter Glut 1 from human red cells was reconstituted into liposomes that were size-fractionated and immobilized in an octyl sulfide-Sephacryl S-1000 column. D-[14C]Glucose was eluted later than L-[3H]glucose from the Glut 1 liposome column (by delta V microliters), apparently because the D-glucose was transported through the liposomes. The corresponding difference with protein-free liposomes was delta V0. The Glut 1 transport retention chromatographic effect, delta VG = delta V - delta V0, 40-50 microliters at pH 7, was nearly constant at pH 6-10 (400 mM NaCl, 23 degrees C, internal liposome volume approximately 240 microliters) but decreased steeply below pH 5 to become zero at pH 3.6. The decrease corresponded to a pKa of approximately 4.4 and was partly reversible above pH 4.7. Similarly, glucose exchange by non-immobilized freeze-thawed proteoliposomes with Glut 1 slowed down drastically as the pH was lowered from pH 5.5 to 4; and octyl glucoside-solubilized Glut 1 lost half its activity in 15 min at pH 4.5 (low ionic strength, 2 degrees C) as shown by glucose exchange determinations at pH 7.2 The results suggest that Glut 1 is inactivated at low pH upon protonation of carboxylate groups of pKa approximately 4.4-4.8. It seems likely that carboxylate groups form hydrogen bonds to transported D-glucose.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Aug
|
| pubmed:issn |
0006-3002
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
15
|
| pubmed:volume |
1150
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
135-46
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1993
|
| pubmed:articleTitle |
Effects of pH on the activity of the human red cell glucose transporter Glut 1: transport retention chromatography of D-glucose and L-glucose on immobilized Glut 1 liposomes.
|
| pubmed:affiliation |
Department of Biochemistry, Biomedical Center, Uppsala University, Sweden.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|