Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

6-Methoxypurine arabinoside (ara-M) exhibits potent activity against varicella-zoster virus (VZV) as a result of ara-M's anabolism to the triphosphate of adenine arabinoside (ara-ATP) in VZV-infected cells. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) enhanced the formation of ara-ATP by inhibiting ara-M demethoxylation. In contrast, deoxycoformycin and coformycin, inhibitors of both adenosine deaminase and AMP deaminase, blocked the formation of ara-ATP and reversed the anti-VZV activity of ara-M. These results indicate that after the initial phosphorylation of ara-M by the VZV-coded thymidine kinase, the monophosphate is demethoxylated by AMP deaminase to form ara-IMP, which is converted to ara-ATP by the sequential actions of the cellular adenylosuccinate synthetase, adenylosuccinate lyase, and nucleotide kinases.
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PMID:Anabolic pathway of 6-methoxypurine arabinoside in cells infected with varicella-zoster virus. 166 24

From a population of wild type S49 cells, a clone, DTB6, was isolated in a single step from selective medium containing thymidine and dibutyryl cyclic AMP that exhibited a 60% deficiency in AMP deaminase (AMP-D) activity. The AMP-D deficiency conferred to the DTB6 cells a striking susceptibility to killing by low concentrations of either adenine or adenosine, the latter in the presence of an inhibitor of adenosine deaminase activity. This growth supersensitivity of DTB6 cells toward adenine could be ameliorated by the addition of hypoxanthine to the culture medium. Immunoprecipitation of AMP-D from wild type and mutant cells revealed that the DTB6 cell line contained markedly diminished amounts of the AMP-D isozyme which reacts with antisera to the predominant isoform expressed in adult kidney. The quantities of the AMP-D isozyme immunoprecipitated by antisera raised to the predominant isoform prepared from adult heart were equivalent in the two cell lines. Although Northern blot analyses revealed no alterations in mRNA sizes or levels encoded by either of the AMP-D genes, Southern blots of genomic DNA hybridized to a cDNA specific for the ampd2 gene revealed the presence of a new BamHI restriction fragment in the DNA of DTB6 cells. These data suggested that a point mutation has occurred in the ampd2 gene of DTB6 cells which encodes the AMP-D isozyme recognized by the kidney antisera. The DTB6 cells also possessed a virtual complete deficiency in thymidine kinase activity. The two enzyme deficiencies were distinguishable. The ability to isolate single step mutants with two seemingly independent biochemical abnormalities raises the speculation that there may be some link between cellular functions responsible for purine nucleotide and thymidine metabolism.
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PMID:Adenylate deaminase deficiency in a mutant murine T cell lymphoma cell line. 236 81

From a mutagenized population of wild type S49 cells, a clone was isolated in a single step that possessed functional and biochemical deficiencies in both AMP deaminase and thymidine kinase activities. This mutant cell line, DTB6, was selected in semi-solid medium containing 1mM thymidine and 1mM dibutyryl cyclic AMP. In comparative growth rate experiments, DTB6 cells were considerably less sensitive than parental cells to the growth inhibitory effects of thymidine. In contrast, DTB6 cells were much more sensitive to the cytotoxic effects of adenine and adenosine. The supersensitivity of DTB6 cells toward adenine could be ameliorated by the addition of hypoxanthine to the culture medium. The growth phenotype of the mutant cells could be attributed to deficiencies in two enzyme activities. First, DTB6 cells possessed a 60-70% deficiency in AMP deaminase activity, although the residual activity appeared kinetically similar to the wild type enzyme. Second, DTB6 cells possessed a virtual complete deficiency in thymidine kinase activity. Both enzyme deficiencies behaved in a recessive fashion in intraspecies hybrids. Revertants of DTB6 cells possessed wild type levels of AMP deaminase activity but remained deficient in thymidine kinase activity, while another revertant of DTB6 cells expressed 11% of the wild type thymidine kinase level but did not perceptibly change its AMP deaminase activity. The ability to isolate single step mutants with two seemingly independent biochemical abnormalities raises the speculation that there may be some link between cellular functions responsible for purine nucleotide and thymidine metabolism.
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PMID:AMP deaminase and thymidine kinase deficiencies in a mutant mouse S49 cell clone. 261 Jan 48