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)

Using 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining, lymphatic capillaries and blood capillaries were distinguished histochemically on cold glycol methacrylate (JB-4) sections of monkey intestines, on the basis of both enzyme characteristics. The specificity of the 5'-Nase reaction was obtained by inhibiting nonspecific ALPase in the 5'-Nase incubation medium including L-tetramisole. This double staining method demonstrated satisfactory isolated visualization of 5'-Nase activity in lymphatic capillaries and of ALPase activity in blood capillaries under light microscopy. The intensity and localization of 5'-Nase activity on the walls of lymphatic capillaries were also determined by the lead-based method under transmission electron microscopy. The intense reaction products of 5'-Nase activity were predominantly deposited on the outer surface of the plasma membrane of the lymphatic endothelial cells.
Lymphology 1991 Sep
PMID:Enzyme-histochemical method for identification of lymphatic capillaries. 172 71

The kidney is the main site of erythropoietin (EPO) formation. Oxygen sensing in the kidney itself plays a major role in the control of EPO synthesis. By in situ hybridization it has been established that the EPO-producing cells are situated in the interstitium of the cortical labyrinth, but they have not been precisely identified. Morphological findings provide new insights into the location and mechanism of oxygen sensing in the kidney. In addition to causing an increase in the number of cells containing EPO messenger RNA, anemia provokes structural changes exclusively in the cortical labyrinth. Specifically, the fibroblasts become enlarged and show increased activity of 5'-nucleotidase, and the S1 segment of the proximal tubule shows similar alterations as in various models of hypoxia. Thus, structures that are situated in the close vicinity of the EPO-producing cells appear to be sensitive to decreased oxygen delivery.
Klin Wochenschr 1991 Sep 03
PMID:Structure-function correlations in erythropoietin formation and oxygen sensing in the kidney. 175 79

It has been reported recently that adenosine and ATP produce dose- and tone-dependent responses in the feline pulmonary vascular (PV) bed. The present study was undertaken to investigate the mechanisms mediating vasoconstrictor (VC) responses to adenosine and ATP in the intact-chest, spontaneously breathing cat under conditions of controlled blood flow and constant left atrial pressure. The order of potency of adenosine receptor agonists to produce VC in the PV bed was the selective adenosine A1 receptor agonist R-phenylisopropyladenosine greater than the mixed A1, A2 receptor agonist, adenosine greater than the selective adenosine A2 receptor agonist, 2-phenylaminoadenosine. The dose-related increase in lobar arterial pressure in response to adenosine was blocked by an adenosine (P1) receptor antagonist, BWA1433U, the cyclooxygenase inhibitor, meclofenamate, and the thromboxane A2 receptor antagonist, SQ29548. The order of potency of ATP analogs to produce VC in the PV bed was alpha,beta-methylene ATP (alpha,beta-meATP) much greater than beta,tau-methylene ATP greater than ATP. BWA1433U inhibited VC responses to ATP without affecting responses to its degradation-resistant analogs beta,tau-methylene ATP and alpha,beta-meATP. In the presence of BWA1433U and a continuous intralobar infusion of the selective 5'-nucleotidase inhibitor, alpha,beta-methyleneadenosine-5'-diphosphate, ATP VC responses are significantly enhanced compared to those after BWA1433U. alpha,beta-Methyleneadenosine-5'-diphosphate had no effect on the VC response to U44069 after BWA1433U. Meclofenamate significantly inhibited the vasoconstrictor responses to ATP but not to alpha,beta-meATP.(ABSTRACT TRUNCATED AT 250 WORDS)
J Pharmacol Exp Ther 1991 Sep
PMID:Adenosine and ATP produce vasoconstriction in the feline pulmonary vascular bed by different mechanisms. 183 63

Plasma membrane vesicles were purified from rat aortic myocytes by centrifugation in a discontinuous sucrose gradient. Vesicles were prepared in the presence or absence of five proteinase inhibitors (aprotinin, benzamidine, leupeptin, pepstatin A and phenylmethylsulfonyl fluoride). The proteinase inhibitors decreased the Vmax by 3.4-fold and had no effect on the Km for Ca2+ of Na+ gradient-dependent 45Ca2+ influx. The proteinase inhibitors had no direct effect on exchange activity, and they had no effect on membrane purity as indicated by 5'-nucleotidase activity. Removing the proteinase inhibitors or adding trypsin or chymotrypsin increased exchange activity approx. 2-fold. The Vmax of exchange activity in intact aortic myocytes is approx. 10-fold higher than the Vmax in plasma membrane vesicles prepared in the presence of proteinase inhibitors. Exchange activity in plasma membrane vesicles is only a sixtieth of the expected value, because the vesicles have approx. 7-fold higher 5'-nucleotidase activity and approx. 6-fold higher specific exchange activity than the crude homogenate. The large loss of exchange activity may be caused by a change in a regulatory domain of the exchanger because endogenous proteolysis restores some of the activity lost during vesicle preparation.
Biochim Biophys Acta 1991 Sep 10
PMID:Sodium-calcium exchange in membrane vesicles from aortic myocytes: stimulation by endogenous proteolysis masks inactivation during vesicle preparation. 189 60

The inosinate dehydrogenase (IMPD) inhibitors ribavirin, tiazofurin and mycophenolic acid were found to stimulate by as much as 20-fold the anabolism of the anti-HIV agent 2' ,3'dideoxyguanosine to its 5'-diphosphate (ddGDP) in a human T-cell culture system (Molt-4 cells). Stimulation of the further conversion to ddGTP (the active form of the drug) was lesser in magnitude but still highly significant (up to 4-fold at appropriate concentrations of ribavirin or tiazofurin). In parallel with these increases, the inhibitors also produced increases of up to 35-fold in IMP levels. These results support the proposal that the initial phosphorylation of ddGuo is catalyzed by a phosphotransferase (5'-nucleotidase) which utilizes IMP as its phosphate donor (Johnson and Fridland, [1989] Molec. Pharmacol. 36, 291-295). Concomitant with this increase in 5'-phosphorylation of ddGuo, an increase in its anti-HIV activity of up to 6.5-fold was observed when this agent was combined with ribavirin (5 microM) in the H9 [corrected] cell assay system.
Biochem Biophys Res Commun 1990 Sep 28
PMID:Inhibitors of IMP dehydrogenase stimulate the phosphorylation of the antiviral nucleoside 2' ,3'-dideoxyguanosine. 197 86

The growth inhibitory activity of tiazofurin toward adenosine kinase deficient Chinese hamster ovary (CHO) cells was partially reversed by the presence of nicotinamide riboside. Similarly, the formation of tiazofurin 5'-monophosphate and the active metabolite, tiazofurin 5'-adenine dinucleotide could be partially inhibited by 100 microM nicotinamide riboside in CHO cells and substantially inhibited (80-90%) in adenosine kinase deficient cells. Tiazofurin phosphorylating activity from CHO cell extracts was resolved into two peaks by DEAE-cellulose chromatography. The first peak of activity was identified as adenosine kinase (ATP:adenosine 5'-phosphotransferase, EC 2.7.1.20). The second peak of activity correlated with a previously described 3-deazaguanosine phosphorylating activity that was identified as a nicotinamide ribonucleoside kinase. Contaminating purine nucleoside phosphorylase was removed by sedimentation through a sucrose density gradient which also resolved the tiazofurin phosphorylating activity into two peaks, one requiring just ATP and the other requiring both ATP and IMP. Of the substrates tested with the lower density peak, nicotinamide riboside was most efficient and was the only natural substance that competed well with tiazofurin for phosphorylation, substantiating its suggested identity as a nicotinamide ribonucleoside kinase. The apparent Km value for nicotinamide riboside (2 microM) was significantly less than that for tiazofurin (13.6 microM). ATP was the best phosphate donor; CTP and UTP were utilized less efficiently and IMP did not support the reaction. The best substrate for the higher density peak of tiazofurin phosphorylation was inosine and both ATP and IMP were required for the reaction, suggesting its identity as a 5'-nucleotidase. In summary, it appears that adenosine kinase, nicotinamide ribonucleoside kinase, and 5'-nucleotidase may all contribute to the phosphorylation of tiazofurin in CHO cells.
Cancer Res 1990 Sep 01
PMID:Tiazofurin is phosphorylated by three enzymes from Chinese hamster ovary cells. 214 86

Five enzyme histochemical reactions were used to characterize calf, goat kid and lamb Peyer's patches. 5'-nucleotidase and acid phosphatase gave a reticular pattern of staining in follicular and interfollicular regions, respectively. Different subpopulations of fibroblastic reticulum cells were suggested for the T cell area, the dome/corona region, and the follicle capsule. The T cell area and the neck portion of the follicle showed a positive reticular reaction with alkaline phosphatase and non-specific esterase. Follicular dendritic cells were positive for Mg2(+)-ATPase in the follicle centre, contrasting with a negative reaction in the periphery. Dendritic cells prevalent in the dome and T cell area showed a Mg2(+)-ATPase reactivity. Macrophages were stained with non-specific esterase and acid phosphatase. No principal differences were found in cell populations between the three species or between fetuses in late gestation and postnatal animals, although the size of the respective compartments varied.
Vet Immunol Immunopathol 1990 Sep
PMID:Organization of ruminant Peyer's patches as seen with enzyme histochemical markers of stromal and accessory cells. 214 25

5'-Nucleotidase, a prominent nucleoside-producing ectoenzyme of glial plasma membranes, was studied by enzyme cytochemistry in the superior cervical ganglion of the rat under normal conditions and after pre- and postganglionic axotomy. In normal ganglia 5'-nucleotidase was restricted to capillary endothelial cells, localized both on the luminal surface and in pinocytotic vesicles. Following preganglionic axotomy, the number of enzyme-positive endothelial vesicles increased, whereas no 5'-nucleotidase was found on reactive Schwann cells during phagocytosis of degenerating preganglionic axon terminals. After postganglionic axotomy an even stronger increase in enzyme-containing endothelial vesicles occurred. In addition, 5'-nucleotidase activity became detectable on the plasma membrane of Schwann cells and proliferating satellite cells, which participate in the detachment of synapses from axotomized neurons. Fibroblasts in the endoneuronal connective tissue of regenerating ganglia also exhibited 5'-nucleotidase on their surface. The results obtained suggest that 5'-nucleotidase may be related to specific metabolic requirements of Schwann and satellite cells during regeneration and that these requirements differ from those of reactive Schwann cells after denervation of the ganglion. Postoperative changes in 5'-nucleotidase activity on endothelial cells and fibroblasts of the ganglion indicate an involvement of these cells in metabolic response elicited by pre- or postganglionic axotomy.
Exp Neurol 1990 Sep
PMID:Cytochemistry of 5'-nucleotidase in the superior cervical ganglion of the rat: effects of pre- and postganglionic axotomy. 220 78

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.
J Biol Chem 1990 Sep 15
PMID:Selective adenosine release from human B but not T lymphoid cell line. 239 45

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.
J Med Chem 1985 Sep
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


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