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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
28
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pubmed:dateCreated |
1990-11-16
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pubmed:abstractText |
The transport of [125I]triiodothyronine ([125I]T3) and [3H]tryptophan ([3H]Trp) by washed rat erythrocytes was studied at 25 degrees C in the presence of leucine in order to block the neutral amino acid transport system L. Eadie-Hofstee plots of initial velocity data gave the following values of Km (micromolar) and Vmax (nanomole/min/10(8) cells): 0.122 +/- 0.007 and 0.140 +/- 0.021 for T3, and 558 +/- 28 and 17.4 +/- 2.3 for Trp (n = 5). The Trp transport system in rat erythrocytes is similar to the human erythrocyte aromatic amino acid-specific system T described by Rosenberg et al. (Rosenberg, R., Young, J. D., and Ellory, J. C. (1980) Biochim. Biophys. Acta 598, 375-384). Unlabeled aromatic amino acids (e.g. Trp, phenylalanine, tyrosine) competitively inhibited [125I]T3 uptake and unlabeled iodothyronine analogues (e.g. T3, D-T3, thyroxine, thyronine) competitively inhibited [3H]Trp uptake. The inhibition constants of these competitors measured with each labeled substrate were highly correlated. N-Ethylmaleimide irreversibly inhibited T3 and Trp transport and each substrate protected the transport system of the other from inactivation by N-ethylmaleimide. The Vmax of T3 and Trp transport by human erythrocytes were 500 and 120 times lower, respectively, than those of rat erythrocytes (0.30 and 126 pmol/min/10(8) cells, respectively). The T3 and Trp transport activities of sheep erythrocytes were undetectable. These results indicate that T3 and Trp either share a common multi-specific transport system or are transported by closely linked systems which interact in the erythrocyte membrane.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Ethylmaleimide,
http://linkedlifedata.com/resource/pubmed/chemical/Phenylalanine,
http://linkedlifedata.com/resource/pubmed/chemical/Thyroxine,
http://linkedlifedata.com/resource/pubmed/chemical/Triiodothyronine,
http://linkedlifedata.com/resource/pubmed/chemical/Tryptophan,
http://linkedlifedata.com/resource/pubmed/chemical/Tyrosine
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
5
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pubmed:volume |
265
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
17000-4
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:2211606-Animals,
pubmed-meshheading:2211606-Biological Transport,
pubmed-meshheading:2211606-Erythrocytes,
pubmed-meshheading:2211606-Ethylmaleimide,
pubmed-meshheading:2211606-Humans,
pubmed-meshheading:2211606-Kinetics,
pubmed-meshheading:2211606-Male,
pubmed-meshheading:2211606-Phenylalanine,
pubmed-meshheading:2211606-Rats,
pubmed-meshheading:2211606-Rats, Inbred Strains,
pubmed-meshheading:2211606-Sheep,
pubmed-meshheading:2211606-Thyroxine,
pubmed-meshheading:2211606-Triiodothyronine,
pubmed-meshheading:2211606-Tryptophan,
pubmed-meshheading:2211606-Tyrosine
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pubmed:year |
1990
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pubmed:articleTitle |
Evidence for a close link between the thyroid hormone transport system and the aromatic amino acid transport system T in erythrocytes.
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pubmed:affiliation |
Unité de Recherche sur la Glande Thyroïde et la Régulation Hormonale (U.96), Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
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