Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The following new 2,4-diamino-6-methylpyrimidines, 5-cyclohexylmethyl, 5-cyclohexylethyl,and 5-(2-naphthyl), as well as 2,6-diaminopurines, 8-adamantyl and8-adamantylmethyl, were synthesized as potential antifolates. Tese, as well as three known compounds, 2,4-diamino-5-cyclohexyl-6-methylpyrimidine, 2,4-diamino-5-(1-naphthyl) -6- methylpyrimidine, and 2,6-diaminopurine, were compared with respect to the inhibition of growth of mammalian cells in culture (TA 3) and with respect to the inhibition of partially purified dihydrofolate reductase. All of the pyrimidines except for the 5-(1maphthyl) derivative were competitive inhivitors of dihydrofolate reductase, with K values ranging from 0.07 to 0.04 pM. They were 2-5 times better as inhibitors of the isolated dihydrofolate reductase than of the cell growth. 2,4-Diamino-5-(1-naphthyl)-6-methylpyrimidine was a noncomptive inhivitor of the enzyme with a Kvalue of 56 pM. This compound was more potent in inhibiting cell growth than the isolated enzyme. indicating that its biological activity was not related to the inhibition of dihydrofolate reductse. All of the purine derivatives were poor growth inhibitors and although some of them inhibited isolated dihydrofolate reductase, their mode of action in cellular system did not seem to concern folate metabolism, as judged by the inability of hypoxanthine, and glycine to provide protection. The implication of these findings as to the structural requirements for inhibition of dihydrofolate reductase is discussed. The implication of these findings as to the structural requirements for inhibition of dihydrofolate reductase is discussed. The pitfalls of the determinition of ID-50 values instead of a complete kinetic analysis in structure-activity studies are emphasized.
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PMID:Synthesis and antifolate activity of new diaminopyrimidines and diaminopurines in enzymatic and cellular systems. 116 22

Nonclassical antifolates, 2,4-diamino-5-substituted-furo[2, 3-d]pyrimidines 3-12 with bridge region variations of C8-S9, C8-N9, and C8-O9 and 1-naphthyl, 2-naphthyl, 2-phenoxyphenyl, 4-phenoxyphenyl, and 2-biphenyl side chains were synthesized as phenyl ring appended analogues of previously reported 2, 4-diamino-5-(anilinomethyl)furo[2,3-d]pyrimidines. The phenyl ring appended analogues were designed to specifically interact with Phe69 of dihydrofolate reductase (DHFR) from Pneumocystis carinii (pc) to afford selective inhibitors of pcDHFR. Additional substituted phenyl side chains which include 2,5-dichloro, 3,4-dichloro, 3,4,5-trichloro, 3-methoxy, and 2,5-dimethoxy analogues 13-17 were also synthesized. The compounds were prepared by nucleophilic displacement of 2,4-diamino-5-(chloromethyl)furo[2,3-d]pyrimidine(2) with the appropriate thiol, amine, or naphthol. Compound 2 was obtained from 2,4-diamino-6-hydroxypyrimidine and 1, 3-dichloroacetone. The compounds were evaluated as inhibitors against DHFR from P. carinii, Toxoplasma gondii, and rat liver. Two analogues, 2,4-diamino-5-[(2'-naphthylthio)methyl]furo[2, 3-d]pyrimidine (5) and 2,4-diamino-5-[(2'-phenylanilino)methyl]furo[2,3-d]pyrimidine (11) showed significant selectivity and potency for pcDHFR compared to trimethoprim. The X-ray crystal structure of 5 with pcDHFR was also carried out, which corroborated the design rationale and indicated a hydrophobic interaction of the naphthalene ring of 5 and Phe69 of pcDHFR which is responsible, in part, for the more than 18-fold selectivity of 5 for pcDHFR as compared with rat liver DHFR.
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PMID:Selective Pneumocystis carinii dihydrofolate reductase inhibitors: design, synthesis, and biological evaluation of new 2,4-diamino-5-substituted-furo[2,3-d]pyrimidines. 954 16

Techniques to incorporate non-natural amino acids (NNAAs) have enabled biosynthesis of proteins containing new building blocks with unique structures, chemistry, and reactivity that are not found in natural amino acids. It is crucial to understand how incorporation of NNAAs affects protein function because NNAA incorporation may perturb critical function of a target protein. This study investigates how the site-specific incorporation of NNAAs affects catalytic properties of an enzyme. A NNAA with a hydrophobic and bulky sidechain, 3-(2-naphthyl)-alanine (2Nal), was site-specifically incorporated at six different positions in the hydrophobic core of a model enzyme, murine dihydrofolate reductase (mDHFR). The mDHFR variants with a greater change in van der Waals volume upon 2Nal incorporation exhibited a greater reduction in the catalytic efficiency. Similarly, the steric incompatibility calculated using RosettaDesign, a protein stability calculation program, correlated with the changes in the catalytic efficiency.
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PMID:Effects of Non-Natural Amino Acid Incorporation into the Enzyme Core Region on Enzyme Structure and Function. 2640 67