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

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

The 5'-deoxy-5'-iodo-substituted analogs of adenosine and inosine are cytotoxic to tumor cells that have high activities of 5'-methylthioadenosine phosphorylase and purine nucleoside phosphorylase, respectively (Savarese, T.M., Chu, S-H., Chu, M.Y., and Parks, R. E., Jr. (1984) Biochem. Pharmacol. 34, 361-367). 5-Iodoribose 1-phosphate (5-IRib-1-P), the common intracellular metabolite of these 5'-iodonucleosides, has been synthesized enzymatically from 5'-deoxy-5'-iodoadenosine via adenosine deaminase from Aspergillus oryzae and human erythrocytic purine nucleoside phosphorylase. The purification and chemical properties of 5-IRib-1-P are described. The analog sugar phosphate inhibited purine nucleoside phosphorylase from human erythrocytes, phosphoglucomutase from rabbit muscle, and 5'-methylthioadenosine phosphorylase from Sarcoma 180 cells with Ki values of 26, 100, and 9 microM, respectively. Enzymes that react with 5-phosphoribosyl 1-pyrophosphate (P-Rib-PP), P-Rib-PP amidotransferase, hypoxanthine-guanine phosphoribosyltransferase, adenine phosphoribosyltransferase, and orotate phosphoribosyltransferase-orotidylate decarboxylase from extracts of Sarcoma 180 cells, were inhibited with Ki values of 49, 465, 307, and 275 microM, respectively. 5-IRib-1-P had no effect on P-Rib-PP synthetase. Since the Ki values of the analog sugar phosphate for 5'-methylthioadenosine phosphorylase and P-Rib-PP amidotransferase are much lower than the Km values of the natural substrates, Pi or P-Rib-PP which are reported to be present at nonsaturating concentrations under physiological conditions, these enzymes could be significantly inhibited by 5-IRib-1-P in intact cells.
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PMID:5-Iodoribose 1-phosphate, an analog of ribose 1-phosphate. Enzymatic synthesis and kinetic studies with enzymes of purine, pyrimidine, and sugar phosphate metabolism. 293 89

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