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 influence of drugs improving sympathoadrenal system status on natural killer (NK) functional activity was studied in lung cancer patients. The activity of adenosine-metabolizing enzymes (adenosine deaminase and 5'-nucleotidase) in NK cells was found significantly altered, suggesting the involvement of this phenomenon in decreasing NK activity under tumor growth. Pharmacological correction of sympathoadrenal system status was followed by an increase in NK functional activity in lung cancer patients.
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PMID:[Increase of the functional activity of natural killers under the effects of the pharmacological correction of the sympathoadrenal system state in patients with lung cancer]. 230 58

The activities (Vmax) of several enzymes of purine nucleotide metabolism were assayed in premature and mature primary rat neuronal cultures and in whole rat brains. In the neuronal cultures, representing 90% pure neurons, maturation (up to 14 days in culture) resulted in an increase in the activities of guanine deaminase (guanase), purine-nucleoside phosphorylase (PNP), IMP 5'-nucleotidase, adenine phosphoribosyltransferase (APRT), and AMP deaminase, but in no change in the activities of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), adenosine deaminase, adenosine kinase, and AMP 5'-nucleotidase. In whole brains in vivo, maturation (from 18 days of gestation to 14 days post partum) was associated with an increase in the activities of guanase, PNP, IMP 5'-nucleotidase, AMP deaminase, and HGPRT, a decrease in the activities of adenosine deaminase and IMP dehydrogenase, and no change in the activities of APRT, AMP 5'-nucleotidase, and adenosine kinase. The profound changes in purine metabolism, which occur with maturation of the neuronal cells in primary cultures in vitro and in whole brains in vivo, create an advantage for AMP degradation by deamination, rather than by dephosphorylation, and for guanine degradation to xanthine over its reutilization for synthesis of GMP. The physiological meaning of the maturational increase in these two ammonia-producing enzymes in the brain is not yet clear. The striking similarity in the alterations of enzyme activities in the two systems indicates that the primary culture system may serve as an appropriate model for the study of purine metabolism in brain.
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PMID:Developmental changes in the activity of enzymes of purine metabolism in rat neuronal cells in culture and in whole brain. 232 47

Acetylcholine and ATP are costored and coreleased during synaptic activity at the electric organ of Torpedo. It has been suggested that released ATP is converted to adenosine at the synaptic cleft, and in turn this nucleoside would depress the evoked release of acetylcholine. In the present communication we have used a chemiluminescent reaction that let us to monitor continuously the presence of adenosine in this preparation. The chemiluminescent reaction is based on the conversion of adenosine into uric acid and H2O2 by adenosine deaminase, nucleoside phosphorylase, and xanthine oxidase enzymes. The hydrogen peroxide has been detected by peroxidase-luminol mixture. The reaction has a sensitivity on the picomol range and discerned between Adenosine, AMP, ADP, and ATP. We have developed this technique in the hope of understanding whether adenosine is released during synaptic activity or it comes from the released ATP. We have studied the release or formation of adenosine in fragments of the electric organ and in isolated cholinergic nerve terminals obtained from it. In both conditions we have followed the effect of potassium stimulation upon the detection of adenosine. Potassium stimulation increased the extracellular adenosine either in slices or the synaptosomal fraction of Torpedo electric organ. The presence of alpha, beta-methylene ADP, an inhibitor of 5'-nucleotidase, inhibits the detection of adenosine, suggesting that extracellular adenosine is a consequence of ectocellular dephosphorylation of released ATP.
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PMID:The release of adenosine at the electric organ of Torpedo. A study using a continuous chemiluminescent method. 232 27

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

The effect of increasing doses of GTP on agonist and antagonist binding to adenosine A1-receptors in different regions of rat brain was studied by autoradiography. A high concentration of GTP (100 microM) practically eliminated the binding of the agonist [3H]N6-cyclohexyladenosine in all regions. However, there were regional differences in the effects of low concentrations of GTP (0.1-10 microM). In some regions, for example the hippocampus, all concentrations of GTP decreased [3H]N6-cyclohexyladenosine binding, by decreasing the Bmax. In other structures, e.g. the superior colliculus, there was a biphasic response to GTP. Concentrations of 0.1-3 microM increased agonist binding, apparently due to a decrease in KD, whereas higher concentrations also decreased binding in these regions. The effects of GTP were mimicked by the stable GTP analogue guanosine-5'-O-(3-thiotriphosphate). GTP (0.5-100 microM) increased the binding of the antagonist [3H]8-cyclopentyl-1,3-dipropylxanthine in all regions, but most markedly in those where GTP had a biphasic effect on agonist binding. Decreasing the levels of endogenous adenosine by increasing the concentration of adenosine deaminase and adding the 5'-nucleotidase inhibitor alpha-beta-methylene adenosine-5'-diphosphate gave an increase in [3H]8-cyclopentyl-1,3-dipropylxanthine binding and diminished the response to GTP. In sections treated with adenosine deaminase and alpha-beta-methylene adenosine-5'-diphosphate, GTP steadily decreased [3H]N6-cyclohexyladenosine binding in all regions. Thus, the GTP-induced increase in both agonist and antagonist binding may be due to a displacement of endogenous adenosine. In the presence of 1 mM EDTA, GTP had a monophasic effect on the binding of [3H]N6-cyclohexyladenosine in all regions. In the presence of 2 mM MgCl2 a biphasic response to GTP was seen in all regions. In EDTA washed sections, the effect of MgCl2 on [3H]N6-cyclohexyladenosine binding was more pronounced in the superior colliculus, where we had observed a biphasic response to GTP. The results suggest that there are regional differences in the effects of GTP on adenosine A1-receptor binding in rat brain, that reflect regional differences in the magnesium-dependent binding of endogenous adenosine, which is bound to the receptor by tight binding, is very difficult to remove, and easily interferes with radioligand binding in in vitro experiments. There may be regional differences in the sensitivity of A1-receptor-G-protein complexes to magnesium, that reflect a heterogeneity of the G-proteins to which the A1-receptors are coupled.
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PMID:Regional differences in the effect of guanine nucleotides on agonist and antagonist binding to adenosine A1-receptors in rat brain, as revealed by autoradiography. 235 51

Intracellular adenosine formation and release to extracellular space was studied in WI-L2-B and SupT1-T lymphoblasts under conditions which induce or do not induce ATP catabolism. Under induced conditions, B lymphoblasts but not T lymphoblasts, release significant amounts of adenosine, which are markedly elevated by adenosine deaminase inhibitors. In T lymphoblasts, under induced conditions, only simultaneous inhibition of both adenosine deaminase activity and adenosine kinase activities resulted in small amounts of adenosine release. Under noninduced conditions, neither B nor T lymphoblasts release adenosine, even in the presence of both adenosine deaminase or adenosine kinase inhibitors. Comparison of B and T cell's enzyme activities involved in adenosine metabolism showed similar activity of AMP deaminase, but the activities of AMP-5'-nucleotidase, adenosine kinase and adenosine deaminase differ significantly. B lymphoblasts release adenosine because of their combination of enzyme activities which produce or utilize adenosine (high AMP-5'-nucleotidase and relatively low adenosine kinase and adenosine deaminase activities). Accelerated ATP degradation in B lymphoblasts proceeds not only via AMP deamination, but also via AMP dephosphorylation into adenosine but its less efficient intracellular utilization results in the release of adenosine from these cells. In contrast, T lymphoblasts release far less adenosine, because they contain relatively low AMP-5'-nucleotidase and high adenosine kinase and adenosine deaminase activities. In T lymphoblasts, AMP formed during ATP degradation is not readily dephosphorylated to adenosine but mainly deaminated to IMP by AMP deaminase. Any adenosine formed intracellularly in T lymphoblasts is likely to be efficiently salvaged back to AMP by an active adenosine kinase. In general, these results may suggest that adenosine can be produced only by selective cells (adenosine producers) whereas other cells with enzyme combination similar to SupT1-T lymphoblasts can not produce significant amounts of adenosine even in stress conditions.
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PMID:Selective adenosine release from human B but not T lymphoid cell line. 239 45

The effect of single (1.4 and 24 h) and long-term (7 days) hydrocortisone intramuscular administration (5 mg/100 g of body mass) on 5'-nucleotidase and adenosine deaminase activities in homogenate and subcellular fractions of the rat brain hypothalamus and hippocampus has been studied. Enzymatic activity of adenosine metabolism in hypothalamus and hippocampus has been shown to undergo changes with the duration of hydrocortisone administration. A possible role of adenosine in the mechanism of glucocorticoid action in the CNS and the regulation of the hypothalamic-pituitary-adrenal axis is under discussion.
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PMID:[The effect of hydrocortisone on the activity of 5'-nucleotidase and adenosine deaminase in the hypothalamus and hippocampus of the rat brain]. 239 37

9-[5'-(2-Oxo-1,3,2-oxazaphosphorinan-2-yl)-beta-D-arabinosyl]adeni ne (1c) and 9-[5'-(2-oxo-1,3,2-dioxaphosphorinan-2-yl)-beta-D-arabinosyl]adeni ne (1d) were synthesized by reaction of 9-[beta-D-arabinofuranosyl]adenine with phosphoryl chloride with 1-amino-3-propanol and 1,3-propanediol, respectively. 1c consisted of a mixture of diastereomers, while 1d was enantiomerically homogeneous. The structures of these compounds were established by spectral (1H NMR, MS, UV) and elemental analyses. Both 1c and 1d were resistant to degradation by 5'-nucleotidase, alkaline phosphatase, venom phosphodiesterase, crude snake venom, adenosine deaminase, and adenylate deaminase. Neither compound was significantly biotransformed by mouse hepatic microsomal preparations in the presence of an NADPH-generating system. Compound 1c was marginally effective at prolonging the life span of mice bearing P-388 leukemia; compound 1d, however, was inactive.
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PMID:Synthesis and biological evaluation of 9-[5'-(2-oxo-1,3,2-oxazaphosphorinan-2-yl)-beta-D-arabinosyl]ade nine and 9-[5'-(2-oxo-1,3,2-dioxaphosphorinan-2-yl)-beta-D-arabinosyl]ade nine: potential neutral precursors of 9-[beta-D-arabinofuranosyl]adenine 5'-monophosphate. 241 27

The distribution of adenosine deaminase-containing neurons and fibers in the spinal cord and medulla was examined and the relationship of dorsal root ganglia neurons containing this enzyme to those containing somatostatin, substance P, fluoride-resistant acid phosphatase (FRAP) and 5'-nucleotidase was determined using immunohistochemical and histochemical methods. In the spinal cord adenosine deaminase-immunoreactive fibers and neurons were confined to layer I and IIo. A similar localization of these was observed in the spinal trigeminal nucleus. In adult animals treated neonatally with capsaicin adenosine deaminase-positive fibers were totally depleted in layer IIo but only partially depleted in layer I. Analysis of lumbar sensory ganglia revealed that small type-B neurons immunoreactive for adenosine deaminase were also immunoreactive for somatostatin but not substance P. In addition, adenosine deaminase-positive neurons lacked histochemical reaction-product for FRAP and exhibited the lowest activity of 5'-nucleotidase. Examination of the neuronal populations containing the two phosphatase enzymes showed that a proportion of neurons exhibiting 5'-nucleotidase activity were devoid of FRAP activity. It is concluded that dorsal root ganglia neurons immunoreactive for adenosine deaminase and somatostatin constitute a single subpopulation of type-B ganglion cells separate from those containing substance P or FRAP. It appears that the lack of coexistence of adenosine deaminase with either FRAP or 5'-nucleotidase cannot be attributed simply to a coexistence of the two latter enzymes since some 5'-nucleotidase-positive neurons lacking FRAP were also devoid of adenosine deaminase-immunoreactivity. Insofar as these three enzymes may contribute to the regulation of transmission processes in primary sensory neurons, our results indicate a minimal functional relationship between adenine nucleoside and nucleotide degrading enzymes in these neurons. In addition, FRAP appears to have some functional independence from 5'-nucleotidase.
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PMID:Anatomical and cytochemical relationships of adenosine deaminase-containing primary afferent neurons in the rat. 241 72

A reliable assay was developed to characterize crude cell homogenates with regard to their adenine phosphoribosyltransferase activities. The 5-phosphoribosyl-1-pyrophosphate (PRPP)-dependent formation of AMP from adenine is followed spectrophotometrically at 265 nm by coupling it with the following two-stage enzymatic conversion: AMP + H2O----adenosine + Pi (5'-nucleotidase); adenosine + H2O----inosine + NH3 (adenosine deaminase). The same principle was applied to develop a spectrophotometric and a radioenzymatic assay for PRPP. The basis of the spectrophotometric assay is the absorbance change at 265 nm associated with the enzymatic conversion of PRPP into inosine, catalyzed by the sequential action of partially purified adenine phosphoribosyltransferase, commercial 5'-nucleotidase, and commercial adenosine deaminase, in the presence of excess adenine. In the radiochemical assay PRPP is quantitatively converted into [14C]inosine via the same combined reaction. Tissue extracts are incubated with excess [14C]adenine. The radioactivity of inosine, separated by a thin-layer chromatographic system, is a measure of PRPP present in tissue extracts. The radioenzymatic assay is at least as sensitive as other methods based on the use of adenine phosphoribosyltransferase. However, it overcomes the reversibility of the reaction and the need to use transferase preparations free of any phosphatase and adenosine deaminase activities.
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PMID:A coupled optical assay for adenine phosphoribosyltransferase and its extension for the spectrophotometric and radioenzymatic determination of 5-phosphoribosyl-1-pyrophosphate in mixtures and in tissue extracts. 244 24


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