Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

5'-Nucleotidase, adenosine phosphorylase, adenosine deaminase and purine nucleoside phosphorylase, four enzymes involved in the utilization of exogenous compounds in Bacillus cereus, were measured in extracts of this organism grown in different conditions. It was found that adenosine deaminase is inducible by addition of adenine derivatives to the growth medium, and purine, nucleoside phosphorylase by metabolizable purine and pyrimidine ribonucleosides. Adenosine deaminase is repressed by inosine, while both enzymes are repressed by glucose. Evidence is presented that during growth of B. cereus in the presence of AMP, the concerted action of 5'-nucleotidase and adenosine phosphorylase, two constitutive enzymes, leads to formation of adenine, and thereby to induction of adenosine deaminase. The ionsine formed would then cause induction of the purine nucleoside phosphorylase and repression of the deaminase. Taken together with our previous findings showing that purine nucleoside phosphorylase of B. cereus acts as a translocase of the ribose moiety of inosine inside the cell (Mura, U., Sgarrella, F. and Ipata, P.L. (1978) J. Biol Chem. 253, 7905-7909), our results provide a clear picture of the molecular events leading to the utilization of the sugar moiety of exogenous AMP, adenosine and inosine as an energy source.
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PMID:Induction and repression of enzymes involved in exogenous purine compound utilization of Bacillus cereus. 627 19

We evaluated the erythrocytes of two patients with hereditary pyrimidine 5'-nucleotidase deficiency. Significant findings included an increased reduced glutathione content, increased incubated Heinz body formation, a positive ascorbate cyanide test, and decreased intraerythrocytic pH. The pentose phosphate shunt activity of the patients' red cells as measured by the release of 14CO2 from 14C-1-glucose was decreased compared to high reticulocyte controls. Glucose-6-phosphate dehydrogenase (G6PD) activity in hemolysates from control erythrocytes was inhibited 43% by 5.5 mM cytidine 5'-triphosphate (CTP) and 50% by 5.5 mM in uridine 5'-triphosphate (UTP) at pH 7.1. CTP was a competitive inhibitor for G6P (Ki = 1.7 mM) and a noncompetitive inhibitor for NADP+ (Ki = 7.8 mM). Glutathione peroxidase, glutathione reductase, and 6-phosphogluconate dehydrogenase were not affected by these compounds. Pentose phosphate shunt activity in control red cell hemolysate at pH 7.1 was inhibited to a similar degree by 5.5 mM CTP or UTP. Since the intracellular concentrations of G6P and NADP+ are below their KmS for G6PD, these data suggest that high concentrations of pyrimidine 5'-nucleotides depress pentose phosphate shunt activity in pyrimidin 5'-nucleotidase deficiency. Thus, this impairment of the pentose phosphate pathway appears to contribute to the pathogenesis of hemolysis in pyrimidine 5'-nucleotidase deficiency hemolytic anemia.
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PMID:Hemolytic anemia in hereditary pyrimidine 5'-nucleotidase deficiency: nucleotide inhibition of G6PD and the pentose phosphate shunt. 628 44

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

Human red cell pyrimidine-5'-nucleotidase (EC 3.1.3.5) was partially purified from the blood of normal subjects by ion-exchange and affinity chromatography. Red cells were lysed in 50 mmol/l Tris-Cl buffer at pH 7.5 containing 1.0 mmol/l dithiothreitol and 0.5 mmol/l EDTA. The lysate was centrifuged and introduced onto a column of Sephadex A-50. After washing, the pyrimidine-5'-nucleotidase activity was eluted from the column with a NaCl gradient from 0 to 200 mmol/l in Tris buffer at pH 7.5. The pyrimidine-5'-nucleotidase was then desalted on Sephadex G-25 and introduced onto a UDP agarose column with a Tris buffer at pH 6.5 containing 150 mmol/l NaCl. This partial purification resulted in an approximately 80,000-fold increase in enzyme concentration. The Km for the partially purified enzyme was 0.32 mmol/l for UMP, 0.16 mmol/l for CMP and 0.11 mmol/l for OMP with a pH maximum of 7.5. This partially purified pyrimidine-5'-nucleotidase was then dialyzed in 50 mmol/l Tris-Cl buffer at pH 7.5 with 0.01 mmol/l CaCl2 and NaCl against 2 X 10(-3) mol/l 1,10-phenanthroline for 24 h at 4 degrees C. This incubation resulted in 73% decrease in enzyme activity which could be restored by the addition of zinc into the mixture, but not by the addition of other divalent metal ions.
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PMID:Partial purification and zinc dependence of human red cell pyrimidine-5'-nucleotidase. 631 32

The persistence of normal thymidine nucleotidase (ThyNase) activity in subjects with pyrimidine nucleotidase (PyrNase) deficiency suggested the possible existence of separate isozymes in normal human erythrocytes. This hypothesis was confirmed by studies of PyrNase-deficient individuals from five unrelated families. Erythrocytes deficient in PyrNase retained normal activity of an enzyme system preferentially active at pH 6.2 with a variety of 2'-deoxyribonucleoside 5'-monophosphate substrates, including those of uridine, thymidine, and cytidine. Lesser activities were observed with the corresponding ribonucleotides. Normal control hemolysates were also found capable of effectively dephosphorylating purine nucleotides (dAMP greater than AMP) when pH was lowered sufficiently from the pH 7.4-8.0 region commonly used in conventional assays. Variations in substrate specificity, pH optima, kinetics, and sensitivity to inactivation by Pb2+ indicated the existence of multiple 5'-nucleotidase isozymes in normal erythrocytes: PyrNase and deoxyribonucleotidase(s) that might function physiologically in the conversion of DNA-derived nucleotides to diffusible nucleosides. Evolution of such a unique 5'-nucleotidase suggests that normal erythroblast maturation and nuclear extrusion is accompanied by a degree of karyolysis sufficient to require dephosphorylation and clearance of DNA degradation products.
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PMID:Identification of thymidine nucleotidase and deoxyribonucleotidase activities among normal isozymes of 5'-nucleotidase in human erythrocytes. 632 Jan 96

Pyrimidine 5'-nucleotidase deficient (PND) erythrocytes contain elevated levels of pyrimidine nucleotides and relatively normal purine nucleotide levels. The composition of this nucleotide pool has been examined by others, but not all of the abnormal red cell metabolites in this disorder were identified. We have isolated and positively confirmed the identity of cytidine diphosphate (CDP)-choline and CDP-ethanolamine from PND red cells using methods including proton FT-NMR, spectroscopy, and comparative mass spectrometry. The concentrations of these and other pyrimidine nucleotidase-deficient erythrocyte nucleotides were determined using anion-exchange high performance liquid chromatography and ultraviolet (u.v.) detection. The pyrimidine diphosphodiesters appear to be the most prominent abnormal pyrimidine nucleotides in PND red cells, accounting for 55% of the total red cell pyrimidine nucleotides in this disorder. It is proposed that these abnormal phosphodiesters may be related to the accelerated hemolysis in PND.
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PMID:Identification of cytidine diphosphodiesters in erythrocytes from a patient with pyrimidine nucleotidase deficiency. 632 Sep 31

The purine and pyrimidine nucleotides in the erythrocytes from two children with 5'-nucleotidase deficiency have been studied using HPLC-technique. The children belonged to the same Norwegian family. In addition to the conventional uracil and cytosine nucleotides relatively high concentrations of UDP-glucose, UDP-N-Ac-glucosamine, CDP-choline and CDP-ethanolamine were found.
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PMID:Cytosine and uracil nucleotides in erythrocytes from two patients with pyrimidine 5'-nucleotidase deficiency. 632 73

The concentrations of red cell CDP (dCDP)-choline and P-choline were measured and compared in normal subjects, in subjects with hemolytic anemia other than that due to pyrimidine-5'-nucleotidase deficiency, in homozygotes for the latter enzymopathy, and in a single subject with a hemolytic syndrome speculatively due to choline phosphotransferase deficiency.
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PMID:Red cell CDP (dCDP)-choline and P-choline in normal subjects and in certain hemolytic syndromes. 633 Nov 56

Induction studies on pyrimidine metabolizing enzymes in E. coli B have shown that the enzymes fall into three distinct groups according to their induction pattern. a) Cytidine deaminase and uridine phosphorylase, are induced by cytidine, CMP and adenosine; no induction was observed with uridine and AMP; b) thymidine phosphorylase is induced by cytidine, adenosine, all deoxyribonucleosides, CMP, deoxyribonucleotides, deoxyribose and deoxyribose-1-phosphate; c) uridine-cytidine kinase, uracil phosphoribosyltransferase, 5'-nucleotidase, thymidine kinase, are uninducible enzymes. Simultaneous addition of cytidine and glucose partially overcomes the cytidine deaminase and uridine phosphorylase induction. Cytidine deaminase reaches its maximum activity levels, in E. coli growing cells in presence of cytidine, two hours before the uridine phosphorylase activity. Maximum glucose repression of cytidine deaminase and uridine phosphorylase was obtained in correspondence of maximum cytidine induction.
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PMID:Induction of pyrimidine nucleoside metabolizing enzymes in E. coli B. 636 Sep 49

The metabolism of deoxycytidine (dCyd) and dCyd nucleotides in Yoshida ascites sarcoma (YS) cells and the host rat liver was investigated with reference to the increased excretion of urinary dCyd. Incorporation of [14C]orotic acid into the livers of rats at the fifth day after the transplantation of YS cells, the time when the amount of excretion of dCyd in urine was near maximal, was 2 times higher than that into the normal rat livers. After the injection of [14C]orotic acid, the ratio of the specific radioactivity of cytidylate to uridylate moieties of the host liver RNA was measured and found to be higher than that of normal rat liver RNA and to be similar to that of YS cell RNA. When [14C]orotic acid was injected into rats followed by the transplantation of YS cells, the radioactivities present in the livers disappeared more rapidly than those in the control rat livers. The activities of pyrimidine de novo synthesis enzymes, such as cytidine triphosphate synthetase (EC 6.3.4.2) and cytidine diphosphate reductase (EC 1.17.4.1), in YS were higher than those in both rat ascites hepatoma AH 7974 and Walker 256 carcinosarcoma, the transplantations of which did not induce increased excretion of dCyd into urine of the hosts. The activities of dCyd kinase (EC 2.7.1.10) and dCyd deaminase (EC 3.5.4.5) in YS cells were lower than those in the other two tumors investigated. The activities of cytidine triphosphate synthetase and cytidine diphosphate reductase in the livers of YS-bearing rats were elevated compared with those in the livers of rat ascites hepatoma AH 7974- or Walker 256 carcinosarcoma-bearing rats and normal rats, while the activities of dCyd kinase, 5'-nucleotidase (EC 3.1.3.5), and dCyd deaminase were similar between normal rat livers and tumor-bearing rat livers. These results suggest that the increased excretion of urinary dCyd in YS-bearing rats could be caused by both the stimulation of the synthesis of dCyd nucleotides and the low activity of dCyd deaminase in YS cells as well as in the host liver.
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PMID:Origin of increased deoxycytidine excretion into urine of rats bearing Yoshida ascites sarcoma. 672 78


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