Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The composition of phosphate metabolites and the intracellular pH in erythrocytes from a patient with hereditary pyrimidine-5'-nucleotidase deficiency were examined using 31P NMR spectroscopy. Several resonances were identified in spectra from intact cells and from extracts. The 2,3-bisphosphoglycerate line intensities were normal but the NTP resonances were about twice normal due to the presence of millimolar quantities of pyrimidine phosphates. Several intense resonances were also observed in the diphosphodiester region of the spectrum. One compound contributing to these lines has been identified as cytidine diphosphocholine. The resonances of NTPs were in a position indicating that the additional triphosphates were also bound by Mg2+. Direct measurement shows that there is a nearly proportional increase in total cell Mg2+ in the patient's cells, in agreement with the interpretation of the spectra. The intracellular pH was about 0.2 unit lower in the patient's erythrocytes. This lower pH is due to the elevation in intracellular fixed negative charges and the shift in permeable anions consequent to the Donnan equilibrium. We suggest that the lower intracellular pH may explain the lower oxygen affinity of these cells in the presence of otherwise normal 2,3-bisphosphoglycerate levels and the increased Mg2+ triphosphates level, because the Mg2+ form of NTPs is known not to alter the oxygen affinity of hemoglobin under physiologic conditions. Furthermore, the lower intracellular pH can also explain the abnormalities in glycolytic intermediates observed for these cells.
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PMID:31P NMR study of erythrocytes from a patient with hereditary pyrimidine-5'-nucleotidase deficiency. 629 65

Extracellular purines are important signalling molecules in the vasculature that are regulated by a network of cell surface ectoenzymes. By using human endothelial cells and normal and leukaemic lymphocytes as enzyme sources, we identified the following purine-converting ectoenzymes: (1) ecto-nucleotidases, NTP diphosphohydrolase/CD39 (EC 3.6.1.5) and ecto-5'-nucleotidase/CD73 (EC 3.1.3.5); (2) ecto-nucleotide kinases, adenylate kinase (EC 2.7.4.3) and nucleoside diphosphate kinase (EC 2.7.4.6); (3) ecto-adenosine deaminase (EC 3.5.4.4). Evidence for this was obtained by using enzyme assays with (3)H-labelled nucleotides and adenosine as substrates, direct evaluation of gamma-phosphate transfer from [gamma-(32)P]ATP to AMP/NDP, and bioluminescent measurement of extracellular ATP synthesis. In addition, incorporation of radioactivity into an approx. 20 kDa surface protein was observed following incubation of Namalwa B cells with [gamma-(32)P]ATP. Thus two opposite, ATP-generating and ATP-consuming, pathways coexist on the cell surface, where basal ATP release, re-synthesis of high-energy phosphoryls, and selective ecto-protein phosphorylation are counteracted by stepwise nucleotide breakdown with subsequent adenosine inactivation. The comparative measurements of enzymic activities indicated the predominance of the nucleotide-inactivating pathway via ecto-nucleotidase reactions on the endothelial cells. The lymphocytes are characterized by counteracting ATP-regenerating/adenosine-eliminating phenotypes, thus allowing them to avoid the lymphotoxic effects of adenosine and maintain surrounding ATP at a steady-state level. These results are in agreement with divergent effects of ATP and adenosine on endothelial function and haemostasis, and provide a novel regulatory mechanism of local agonist availability for nucleotide- or nucleoside-selective receptors within the vasculature.
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PMID:The evidence for two opposite, ATP-generating and ATP-consuming, extracellular pathways on endothelial and lymphoid cells. 1209 90

Studies demonstrated that endogenous levels of estrogen affect the long-term potentiation (LTP) and long-term depression (LTD). ATP and adenosine may play a role in the modulation of LTP. Our laboratory observed in previous studies that inhibitory avoidance task is associated with a decrease in hippocampal ectonucleotidase activities in adult male rats. To explore if ectonucleotidases are modulated in memory formation in female rats, as observed in males, we evaluated the effect of inhibitory avoidance training on synaptosomal NTP Dase and 5'-nucleotidase activities in rat hippocampus from both sexes. The results demonstrated a decrease in ATP, ADP and AMP hydrolysis (37%, 38% and 32%, respectively) immediately after training and a significant inhibition only in ATP hydrolysis (36%) 30 min post-training in male rats. There were no changes in ectonucleotidase activities from female rats. These findings provide support for the view that could exist biochemical differences in ectonucleotidase activities between males and females.
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PMID:Inhibitory avoidance task reveals differences in ectonucleotidase activities between male and female rats. 1567 44