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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
3
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pubmed:dateCreated |
1979-7-25
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pubmed:abstractText |
Techniques have been developed to measure FdUMP, the active metabolite of 5-FUra; thymidylate synthetase (TMP synthase; 5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45), the target enzyme for this antimetabolite; and dUMP, the substrate that competes with FdUMP for binding to TMP synthetase. As little as 0.02 pmol of FdUMP can be quantitated with a competitive ligand binding assay by using homogeneous Lactobacillus casei/MTX TMP synthetase as a binding protein. A new binding assay for TMP synthetase allows detection of 0.005 pmol of enzyme. The quantitative enzymatic conversion of dUMP to [methyl-(14)C]-TMP using 5,10-methylene[(14)C]tetrahydrofolate by pure L. casei TMP synthetase is used as an assay for dUMP with a sensitivity of 10 pmol. Cultured CCRF-CEM human lymphoblastic leukemia cells formed high levels of FdUMP (2.6 nmol per 10(9) cells) within 11 hr after exposure to 30 muM 5-FUra. Tumor cell TMP synthetase levels dropped, and then free FdUMP appeared. The intracellular dUMP pool was low (2-5 nmol per 10(9) cells) in logarithmically growing cultures of several tumor cell lines but expanded rapidly in CCRF-CEM cells on exposure to 5-FUra after enzyme levels decreased. The levels of dUMP found after exposure to 5-FUra are sufficient to severely retard inhibition of TMP synthetase by FdUMP.The methods described are sufficiently sensitive to allow these biochemical parameters of 5-FUra action to be measured in cell culture or in needle biopsy samples of human tumors.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-101234,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-1184747,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-125086,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-1259156,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-14337699,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-151682,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-360064,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4115981,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4263280,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4278001,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4358948,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4505665,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-4716378,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-5003635,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-5044785,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-5166749,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-5538615,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-5781098,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-667828,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-718724,
http://linkedlifedata.com/resource/pubmed/commentcorrection/108681-945269
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
76
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1456-60
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
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pubmed:year |
1979
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pubmed:articleTitle |
Biochemical determinants of tumor sensitivity to 5-fluorouracil: ultrasensitive methods for the determination of 5-fluoro-2'-deoxyuridylate, 2'-deoxyuridylate, and thymidylate synthetase.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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