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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)

This paper deals with a new method for the determination of serum nucleotidase (EC 3.1.3.5). The assay is performed with cytidine-5'-monophosphate as substrate, followed by deamination of the generated cytidine. The principle of the method and the determination of the liberated ammonia by the Berthelot indophenol-reaction are comparable to the Persijn--van der Slik method in which adenosine-5'-monophosphate is used as substrate. The correlation between the results obtained with these two methods was found to be good; the new method has the advantage of higher sensitivity.
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PMID:Determination of serum nucleotidase with cytidine monophosphate as substrate, (I). 109 94

Administration to rats of D-galactosamine (400 mg/kg) produces liver cell death that develops during the first 24 hours. Plasma membranes isolated within the first few hours from these animals show a 40% reduction in 5'-nucleotidase activity and a two-fold increase in maximum negative ellipticity determined by circular dichroism. Simultaneous administration of uridine prevents liver cell death and these early alterations in the plasma membranes. Uridine also prevents cell death if administered for up to 3 hours after galactosamine. The 5'nucleotidase activity reduced when uridine is administered for up to 2-1/2 hours after galactosamine. Changes in the liver calcium ion concentration accompany these plasma membrane alterations. Uridine will prevent and reverse the changes in calcium content in parallel to its ability to reverse the membrane alterations. The significance of these findings with respect to the mechanism of galactosamine-induced liver cell death is discussed.
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PMID:Early, reversible plasma membrane injury in galactosamine-induced liver cell death. 113 5

5'-Nucleotidase in perfused rat hearts, accessible to extracellular substrate [14C]-AMP contained in the perfusate, was compared to a partially purified 5'-nucleotidase from the same organ. Both activities were inhibited by ATP and, more effectively, by the ADP analog adenosine-alpha, beta-methylene diphosphate (APCP). The isolated enzyme showed a competitive inhibitor constant of 5.4 x 10(-8) M for APCP (Km of AMP = 1.4 x 10(-5) M). Although both activities were effectively inhibited by APCP, insufficient knowledge about the selectivity of this agent as a nucleotidase inhibitor does not permit a conclusion on whether or not the extracellular activity is identical to the partially purified enzyme.
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PMID:Inhibition of extracellular and purified 5'-nucleotidase from rat heart. 120 4

The effect of peroxidation on 5'-nucleotidase activity as well as on membrane microviscosity has been investigated in liver plasma membranes from Wistar rats. The peroxidation was performed with 100 microM H2O2 and 200 microM FeSO4 and/or with 5 mM t-butylhydroperoxide. Treatment of the membranes with these oxidizing agents resulted in an elevation of the transition temperatures of the polarization of the lipid fluorescent probes 1,6 diphenyl-1,3,5 hexatriene (DPH), 3-p-(6-phenyl) 1,3,5 hexatriene phenylpropionic acid (PA-DPH) as well as of the fluorescent thiol reagent N-(1-pyrene) maleimide (1-PM). The peroxidation resulted in a decrease of the activity of 5'nucleotidase. Our data support that the increase of membrane microviscosity of the lipid domain regulates the activity of 5'-nucleotidase.
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PMID:Lipid peroxidation causes an increase of lipid order and a decrease of 5'-nucleotidase activity in the liver plasma membrane. 149 43

Spontaneous mouse red-cell rosette formation (M-rosette), Leu 1 (CD 5) monoclonal antibody binding, ecto-nucleotidase enzyme reactions and mitogen responses of peripheral blood lymphocytes in 10 patients with B-cell chronic lymphocytic leukaemia (CLL), in 8 with systemic lupus erythematosus (SLE) and in 10 controls were studied. The numbers of Leu 1 (CD 5) positive B lymphocytes in CLL and SLE were higher than in controls. These are called "autoregulatory" B lymphocytes, which are thought to be independent of T-cell regulatory effects. A significant increase of mouse rosette forming cells (MRFCs) was found in CLL, while in SLE and in controls their number was low. Compared to the B lymphocytes of SLE patients and controls, those of CLL patients showed diminished responses to pokeweed mitogen stimulation parallel to their decreased level of 5'-nucleotidase. Correlations between these markers and the features of isolated M-rosette positive CLL B lymphocytes are discussed.
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PMID:Comparison of some lymphocyte markers in B-cell chronic lymphocytic leukaemia and systemic lupus erythematosus (the B lymphocyte subset). 214 33

The activity of 5-nucleotidase (EC 3.1.3.5) and guanylate kinase (EC 2.7.4.8) in the mitochondria and supernatant of the brain and liver was determined in experiments on Wistar male rats 1, 3, 6, 24 and 48 h after the single total irradiation by gamma-quanta in a dose of 30 Gy. It is established that the activity of 5-nucleotidase in the liver endures phase changes with the predominance of the enzyme activation; in the brain it is higher during the whole period of investigation. The guanylate kinase activity lowers in the both fractions of the organs under study during the whole period of the experiment.
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PMID:[Increase in 5'-nucleotidase and decrease in guanylate kinase activity in the brain and liver of irradiated rats]. 216 69

The activity of metabolic enzymes, adenosine and thymidine, has been studied in the blood serum and lymphocytes of healthy people and oncological patients aged 23-80. An increase in the activity of thymidine kinase (EC 2.7.1.2), an enzyme of thymidine biosynthesis, was observed in the blood serum of oncological patients against a background of a sharp decrease in the activity of thymidine phosphorylase (EC 2.4.2.4), a catabolic enzyme. The revealed enzymic shifts have been observed in breast cancer patients after 36, in patients with the stomach cancer--after 46. It is found that an increase in the activity of adenosine deaminase (EC 3.5.4.4) and 5-nucleotidase of AMP (EC 3.1.3.5) in the blood serum of oncological patients is accompanied by a sharp decrease in the activity of these enzymes in lymphocytes.
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PMID:[Activity of adenosine and thymidine metabolism enzymes in the blood of cancer patients of various ages]. 233 24

Adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission were measured in peritoneal macrophages of Syrian hamsters in the growth process of tumours with different grade of malignancy. The adenosine deaminase activity was established to decrease, while the 5'nucleotidase activity--to increase in macrophages after the subcutaneous injection of tumour cells with high level of malignancy as compared with these values in normal cells. This is accompanied by a decrease of the macrophage chemiluminescence during the whole experimental period. At the same time adenosine deaminase and 5'-nucleotidase activities as well as chemiluminescence emission in peritoneal macrophages of hamsters treated with low-malignancy cells do not differ from these values in the control group.
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PMID:[Activity of adenosine metabolism enzymes and spontaneous chemiluminescence in macrophages in the tumor growth process]. 254 8

2',3'-Dideoxyinosine (ddlno) is a potent and selective inhibitor of human immunodeficiency virus in human lymphoid cells and monocytes/macrophages. Earlier studies [J. Biol. Chem. 263:15354 (1988)] showed that anabolism of ddlno in human lymphoid cells is mediated via an initial step of phosphorylation and subsequent amination to dideoxy-AMP via adenylosuccinate synthetase/lyase. Evidence was obtained that neither adenosine kinase nor deoxycytidine kinase is involved in the phosphorylation of this compound in human lymphoid cells. We now find that, in the presence of MgCl2, KCl, and inosine-5'-monophosphate as phosphate donor, purified cytosolic 5'-nucleotidase catalyzed the phosphorylation of ddlno. Although not phosphate donors, ATP, diadenosine tetraphosphate, and glycerate-2,3-bisphosphate stimulate this phosphorylation by the nucleotidase 4-5-fold. In addition to ddlno, the antiviral nucleoside analogs 2',3'-dideoxyguanosine and carbovir were substrates for this enzyme. The relative phosphorylation of these compounds varied with the concentration of the phosphate donor IMP. Approximate Km values of the nucleotidase for inosine, ddlno, dideoxyguanosine, and carbovir were, respectively, 3.4, 0.5, 0.9, and 1.7 mM. Although the substrate activity of dideoxynucleosides is inefficient, it appears likely that this nucleotidase is responsible for the metabolism of these compounds to their active nucleotides, yielding antiviral activity in human lymphoid cells.
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PMID:Phosphorylation of 2',3'-dideoxyinosine by cytosolic 5'-nucleotidase of human lymphoid cells. 254 85

The 5-AMPase activity of the ectoenzyme 5-nucleotidase has been measured in a variety of cell lines, using intact cells. Human cell types showed two orders of magnitude higher enzyme activity than mouse cell lines. The ectoenzyme is inhibited by adenosine 5-(alpha, beta-methylene) diphosphate and Concanavalin A. A different extent of 5-nucleotidase lectin inhibition was observed in the studied cell lines, suggesting that the corresponding ectoenzymes are glycoproteins with a different type or degree, or both, of glycosylation. The 5-nucleotidase activity increased during subculture and decreased after cell transformation. Generally, the 5-nucleotidase activity was two- to five-fold higher in monolayer than in suspension cell culture. A relation between cell growth and 5-AMPase activity was also observed. Enzyme activity increased at the end of the lag phase (glioblastoma cells) or during the exponential phase (the other two cell lines). After confluence, the activity decreased to the initial or even lower range of activity. Observed activity variations with cell proliferation correlate with modifications of 5-AMPase activity during subculture.
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PMID:5-nucleotidase activity in cultured cell lines. Effect of different assay conditions and correlation with cell proliferation. 255 60


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