Multiple forms of L1210 dihydrofolate reductase differing in affinity for methotrexate.

@article{Duffy1984MultipleFO,
  title={Multiple forms of L1210 dihydrofolate reductase differing in affinity for methotrexate.},
  author={T. Duffy and S. Beckman and F. M. Huennekens},
  journal={Biochemical and biophysical research communications},
  year={1984},
  volume={119 1},
  pages={
          352-8
        }
}
Dihydrofolate reductase, purified from a Methotrexate-resistant subline (R6) of L1210 mouse leukemia cells, consists of two forms (designated 1 and 2) differing in affinity for the drug. Form 1 is more sensitive to inhibition by Methotrexate. Form 2 is more heat-labile, but it can be stabilized by bovine serum albumin or NADPH. Isoelectric focusing resolves 1 and 2; pI values are 7.4 and 8.2. Forms 1 and 2 comprise about 10 and 90% of the total protein, but 1 has at least a 2-fold higher… Expand
11 Citations
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Activating agents appear to induce a more open (and labile) conformation of the enzyme, which leads to increased affinity for MTX accompanied, in some instances, by increased catalytic activity. Expand
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These conclusions are consistent with the well-known ability of eukaryotic dihydrofolate reductases to exhibit increased catalytic activity when treated with salts, chaotropes, or cysteine-modifying agents. Expand
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Two species of DHFR were identified in wild-type L1210 murine leukemia cells by analysis of the kinetics of the binding of MTX and dissociation of the MTX-enzyme complex at pH 5.0 and pH 7.2. The twoExpand
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  • Molecular and biochemical parasitology
  • 1986
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Results presented here indicate that pyrimethamine resistance of P. falciparum depends on a modified dihydrofolate reductase, which shows less affinity for pyrimEThamine and dihydROfolate. Expand
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Scatchard analysis of the [3H]-methotrexate binding data by a colon tumor sample suggests that the two binders of methotrexate may be the two forms of dihydrofolate reductase having different affinities for this anticancer drug. Expand
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The efficiency of these newly designed 2,4-diamino-5-(substituted benzyl) pyrimidines was confirmed by their strong inhibitory effect on plasmodial dihydrofolate reductase as well as by in vitro screening against drug-sensitive and-resistant strains of P. falciparum. Expand
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Information about the drug-binding sites, along with computer graphic modeling, then provides guidance for the chemical synthesis of compounds tailored to fit with a high degree of specificity and affinity. Expand
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Mechanisms by which malignant cells may become resistant to chemotherapeutic agents are reviewed, with emphasis on methotrexate resistance. At least four mechanisms of resistance have been describedExpand
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TLDR
Five-year disease-free survival rates are only 50% and 10%–15%, respectively, in these diseases, almost certainly due to the development of drug resistance even to the combination chemotherapy programs utilized to treat these diseases. Expand
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TLDR
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TLDR
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TLDR
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Abstract Dihydrofolate reductase (EC 1.5.1.3), purified to homogeneity from an amethopterin-resistant subline (R6) of cultured L1210 murine leukemia cells, has been used to study enzyme-substrate andExpand
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