Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The changes in the biochemical parameters of peritoneal macrophages and their coupling to the secretory and phagocytic functions in CH3A mice during the growth of the reinoculated solid hepatoma 22a were studied. The DNA and RNA synthesis during the active tumour growth was more intense than that in resident macrophages. The activity of uridine kinase increased up to 156.0 +/- 12.0 nmol/hour/10(8) but was absent in resident macrophages. This was accompanied by a 7.2-fold increase of interleukin-1 synthesis as determined by the [3H]thymidine incorporation into thymocyte DNA in response to concanavalin A administration to C3H mice. Similar changes were observed in peptone-stimulated macrophages. A specific feature of macrophages from tumour-bearing mice was the impairment of activity of purine exchange enzymes and the efficiency of phagocytosis that were unobserved in peptone-stimulated macrophages. The activity of adenosine deaminase and purine nucleoside phosphorylase was inhibited as a result of their preincubation with zymosan, a phagocytosis-stimulating agent. This was accompanied by a significant decrease of the first chemiluminescence peak resulting from disturbances in Fc-reception. Macrophages of tumour-bearing animals possessed an increased 2.2-fold activity of membrane-bound AMP 5'-nucleotidase concomitant with the lack or decrease of the amplitude of the second chemiluminescence peak reflecting the disturbances in digestion resulting from phagocytosis.
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PMID:[Change in activity of enzymes for purine metabolism and RNA and DNA biosynthesis in macrophages, reflecting impairment of their functions in neoplastic growth]. 248 7

Using radiochemical methods, we determined the activities of various enzymes of purine and pyrimidine metabolism in homogenates of human skeletal muscle and of cultured human muscle cells. Results show a large discrepancy between the enzyme activities in muscle and cultured cells. With regard to purine metabolism, adenylate (AMP) deaminase activity was only 1-3% in cultured cells compared to that in muscle, whereas the activity of adenosine deaminase, purine-nucleoside phosphorylase, adenosine kinase, adenine phosphoribosyltransferase and hypoxanthine phosphoribosyltransferase was 7-15-fold higher in the cultured cells. The enzymes of pyrimidine metabolism, orotate phosphoribosyltransferase, orotidine 5'-monophosphate decarboxylase and uridine kinase showed activity of 100-200-fold higher in cultured cells than in adult muscle. The differences in enzyme activity are probably related to the low differentiation stage and the absence of contractile activity in the cultured muscle cells. Care must be taken when using these cells as a model for studying purine and pyrimidine metabolism of adult myofibers.
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PMID:Purine and pyrimidine metabolism in human muscle and cultured muscle cells. 283 95

Biosynthesis of purine and pyrimidine nucleotides was distinctly increased in leukocytes of patients with chronic myeloid leukosis, involving mainly the reutilization of preformed nitrogenous bases and nucleosides. An increase in the rate of 14C-orotate and 3H-uridine incorporation into the pyrimidine pool of myeloid leukosis cells correlated with stimulation of uridine kinase and orotidine monophosphate pyrophosphorylase, catalyzing biosynthesis of pyrimidine nucleotides in the reutilization pathway and de novo, respectively. The system of adenosine deaminase, providing the high rate of adenosine incorporation into the nucleotide pool, was apparently responsible mainly for the rate of reutilization synthesis of purine nucleotides in normal and leukemic leukocytes. Synthesis of RNA in leukocytes of patients with chronic myeloleukemia was increased mainly due to consumption of nucleotides formed via the reutilization pathway.
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PMID:[Metabolism of nucleotides and RNA in leukocytes in chronic myeloleukosis]. 657 34

The introduction of human p53 with mutation at codon 273 into Rat-1 cells induces changes in the salvage pathway of nucleotide synthesis. In cells expressing the mutant p53 the activities of hypoxanthine phosphoribosyl transferase (HPRT) and thymidide kinase (TK) decrease 3.5- and 2-3-fold, respectively, while the activities of adenosine deaminase and uridine kinase, in contrast, increase correspondingly 2.5- and 1.5-fold. On the other hand, in cells transformed by ras oncogene, which causes dramatical reduction in HPRT activity as well as enhancement of TK function, the expression of exogeneous p53 leads to the opposite effects and causes the reversion of activities of both enzymes to the levels found in parental cells.
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PMID:Human p53, mutated at codon 273, causes distinct effects on nucleotide biosynthesis salvage pathway key enzymes in Rat-1 cells and in their derivatives expressing activated ras oncogene. 833 54