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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1986-7-2
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pubmed:abstractText |
A quenched-flow apparatus and a newly developed automated syringe system have been used to measure initial rates of D-[14C]glucose transport into human red blood cells at temperatures ranging from 0 degrees to 53 degrees C. The Haldane relationship is found to be obeyed satisfactorily at both 0 and 20 degrees C, but Arrhenius plots of maximum D-[14C]glucose transport rates are non-linear under conditions of both equilibrium exchange and zero trans influx. Fitting of the data by non-linear regression to the conventional model for glucose transport gives values at 0 degrees C of 0.726 +/- 0.0498 s-1 and 12.1 +/- 0.98 s-1 for the rate constants governing outward and inward movements of the unloaded carrier molecule and 90.3 +/- 3.47 s-1 and 1113 +/- 494 s-1 for outward and inward movements of the carrier-glucose complex. Activation energies for these four rate constants are respectively 173 +/- 3.10, 127 +/- 4.78, 88.0 +/- 6.17 and 31.7 +/- 5.11 kJ X mol-1. These parameters indicate that at low temperatures the marked asymmetry of the transport mechanism arises mainly from the high proportion of inward-facing carriers and carrier-glucose complexes, and that there is a relatively small difference between the affinities of the carrier for glucose in the inward and outward-facing conformations. At high (physiological) temperatures the carrier is fairly evenly distributed between outward- and inward-facing conformations and the affinity for glucose is about 2.5-times greater outside than inside.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
May
|
pubmed:issn |
0006-3002
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pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
28
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pubmed:volume |
857
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
146-54
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:3707948-Biological Transport, Active,
pubmed-meshheading:3707948-Blood Glucose,
pubmed-meshheading:3707948-Erythrocytes,
pubmed-meshheading:3707948-Humans,
pubmed-meshheading:3707948-Kinetics,
pubmed-meshheading:3707948-Mathematics,
pubmed-meshheading:3707948-Monosaccharide Transport Proteins,
pubmed-meshheading:3707948-Temperature
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pubmed:year |
1986
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pubmed:articleTitle |
The kinetics of glucose transport in human red blood cells.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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