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 plasma membranes isolated from rat liver bound 125I-labelled ([125I]) synthetic [Asu1,7]eel calcitonin (CT), with increasing concentrations of [125I]CT. This specific binding was completely saturated at a concentration of 0.5 nM CT. A high affinity Ca2+-stimulated, Mg2+-dependent ATPase [(Ca2+-Mg2+)-ATPase] activity in the plasma membranes was significantly decreased by the presence of a very low concentration of CT (7.4 pM), although the hormone did not affect the activity of the plasma membrane 5'-nucleotidase. The concentration of CT needed for maximal inhibition of (Ca2+-Mg2+)-ATPase in the plasma membranes was less than 0.74 nM. The plasma membranes washed with 10(-3)% digitonin did not show an inhibitory effect of CT on (Ca2+-Mg2+)-ATPase activity, while the reagent did not have a significant effect on the enzyme. These results suggest that the inhibition of (Ca2+-Mg2+)-ATPase activity may be part of the mechanism by which CT elevates cytosolic Ca2+ in liver cells.
Acta Endocrinol (Copenh) 1985 Sep
PMID:Regulation of (Ca2+-Mg2+)-ATPase activity by calcitonin binding to rat liver plasma membranes. 299 35

Several B lymphoblastic cell lines are known to be relatively resistant to the combination of 2'-deoxyadenosine with an adenosine deaminase inhibitor. These cell lines are believed to have a greater capacity to dephosphorylate 2'-deoxyadenosine nucleotides, thus preventing excessive accumulation of potentially toxic metabolites. In this study, the 2'-deoxynucleoside 5'-monophosphate dephosphorylating activities of human peripheral lymphocytes were examined. Peripheral lymphocytes have at least three nucleotide 5'-monophosphate nucleotidases distinguished by different pH optimums, substrate preference, Mg2+ requirement, inhibitors, and molecular weights. Two of the enzymes appeared to be cytosolic, only one of which had significant substrate activity with dAMP. This enzyme had an acidic pH optimum (5.0), no Mg2+ requirement, was inhibited by tartrate, and demonstrated broad substrate specificity. The other cytosolic nucleotidase required Mg2+, had a pH optimum of 5.5 to 6.0, was activated by 2'-deoxyinosine, and demonstrated a substrate preference for 3'- and 5'-monophosphate 2'-deoxynucleosides of hypoxanthine, guanine, uracil, and thymine. The third enzyme, ecto 5'-nucleotidase, is associated with the cell membrane. Although the ecto 5'-nucleotidase activity was higher in the B lymphocytes, the cytosolic nucleotidases were similar in activity in the T and B lymphocytes.
Biochem Pharmacol 1985 Sep 01
PMID:Nucleotidase activities of human peripheral lymphocytes. 299 75

In this study we report an overall procedure for the isolation of both human polymorphonuclear neutrophils and their plasma membrane, by means of self-generating Percoll gradients. After efficient purification (40% yield), neutrophils were lysed by nitrogen cavitation and cellular structures quickly isolated in a one-step procedure. Plasma membrane recovery was monitored by [3H]concanavalin A and 5'-nucleotidase (EC 3.1.3.5) activity. We showed the latter activity is indeed present in human neutrophils. The procedure resulted in a good yield of plasma membrane, since 45% and 55% of total 5'-nucleotidase and [3H]concanavalin A activity, respectively, were recovered within two gradient fractions. Depending on the final pH of the Percoll gradient medium, endoplasmic reticulum markers contaminated either the plasma membrane or the granule fractions. At pH 9.05, NADH-ferricyanide reductase activity clearly separated from plasma membrane markers and displayed the same profile as CDPcholine:diacylglycerolcholine phosphotransferase (EC 2.7.8.2), a typical enzyme of endoplasmic reticulum. These results emphasize the need for strict monitoring of the pH of the gradient medium in subcellular fractionation of neutrophils.
Biochim Biophys Acta 1985 Sep 25
PMID:A rapid isolation procedure of plasma membranes from human neutrophils using self-generating Percoll gradients. Importance of pH in avoiding contamination by intracellular membranes. 299 31

Addition of NADH, but not NAD+ or NADPH, to rat liver plasma membranes resulted in the increase of their 5'-nucleotidase activity. NADH-dependent activation of 5'-nucleotidase was significantly suppressed by atebrine, an inhibitor of NADH dehydrogenase of plasma membranes, and completely abolished by 2,4-dinitrophenol (2 X 10(-4)M) and Triton X-100 (2%). Inhibitors of electron transfer in the mitochondrial respiratory chain, rotenone and potassium cyanide, failed to affect 5'-nucleotidase activity in both the presence and absence of NADH. The data obtained give reasons to suggest a redox-dependent mechanism of 5'-nucleotidase activation in rat liver plasma membranes.
FEBS Lett 1985 Sep 23
PMID:Redox-dependent activation of 5'-nucleotidase in rat liver plasma membranes. 299 24

We compared the properties of the ectonucleotidases (nucleoside triphosphatase, EC 3.6.1.15; nucleoside diphosphatase, EC 3.6.1.6; 5'-nucleotidase, EC 3.1.3.5) in intact pig aortic smooth-muscle cells in culture with the properties that we previously investigated for ectonucleotidases of aortic endothelial cells [Cusack, Pearson & Gordon (1983) Biochem. J. 214, 975-981]. In experiments with nucleotide phosphorothioate diastereoisomers, stereoselective catabolism of adenosine 5'-[beta-thio]triphosphate, but not of adenosine 5'-[alpha-thio]triphosphate, by the triphosphatase and stereoselective catabolism of adenosine 5'-[alpha-thio]diphosphate by the diphosphatase were found, as occurs in endothelial cells. In contrast with endothelial ecto-5'-nucleotidase, the smooth-muscle-cell enzyme catabolized adenosine 5'-monophosphorothioate (AMPS) to adenosine: the affinity of the enzyme for AMPS was greater than for AMP, and Vmax for AMPS was about one-sixth that for AMP. In both cell types AMPS was an apparently competitive inhibitor of AMP catabolism by 5'-nucleotidase. The relative rates of catabolism of nucleotide enantiomers in which the natural D-ribofuranosyl moiety is replaced by an L-ribofuranosyl moiety were similar to those in endothelial cells. No ectopyrophosphatase activity was detected in smooth-muscle cells, in contrast with endothelial cells, where modest activity is present.
Biochem J 1985 Sep 01
PMID:Characterization of ectonucleotidases on vascular smooth-muscle cells. 299 2

By means of histochemical techniques at light and electron microscopic levels, as well as immunomorphological, biochemical and immunochemical methods localization and dynamics of alkaline phosphatase and 5'-nucleotidase contents have been determined in anlages of long tubular bones in 85 human embryos and prefetuses from the 6th up to 12th week of the intrauterine development, obtained as a result of artificial abortions in healthy women. The greatest activity of the enzymes studied is revealed in areas of an intensive osteogenesis and mineralization. Also, by means of the immunofluorescent method alkaline phosphatase of a placental type is revealed, that is not revealed, however, immunochemically. With increasing time of the intrauterine development, thermostability of alkaline phosphatase increases.
Arkh Anat Gistol Embriol 1985 Sep
PMID:[Alkaline phosphatase and 5'-nucleotidase in early osteogenesis in man]. 299 6

Intact synaptosomes isolated from the electric organ of the electric ray Torpedo marmorata contain, at their surface, enzyme activities for the hydrolysis of externally applied nucleoside phosphates. The diazonium salt of sulfanilic acid, as a low-molecular-weight, slowly permeating, covalent inhibitory agent, selectively blocks these enzyme activities and leaves intracellular lactate dehydrogenase intact. The ectoenzymes comprise both a nucleoside triphosphate and diphosphate phosphohydrolase, as well as a 5'-nucleotidase. Activity of nonspecific ectophosphatases is absent. The nucleoside triphosphatase hydrolyzes almost equally well ATP, GTP, CTP, UTP, and ITP and is activated to a similar degree by Mg2+ or Ca2+. It has a high affinity for ATP (Km for ATP in the presence of Mg2+, 75 microM; in the presence of Ca2+, 66 microM). Maximal rates in the presence of Mg2+ and Ca2+ were very similar (34.8 and 32.5 nmol of Pi/min/mg of synaptosomal protein, respectively). Either Mg-ATP or Ca-ATP can act as a true substrate. ADP inhibits hydrolysis of ATP, but AMP is without effect. The nucleoside triphosphatase is not inhibited significantly by a number of inhibitors of mitochondrial Mg2+-ATPase or of Ca2+ + Mg2+-ATPases. It is, however, considerably inhibited by filipin and quercitin. The capacity of intact synaptosomes to hydrolyze also extracellular ADP, GDP, AMP, GMP, and IMP suggests that the nucleoside triphosphatase is part of an enzyme chain that causes complete hydrolysis of the respective nucleoside triphosphate to the nucleoside. We conclude that the cholinergic nerve terminals of the Torpedo electric organ can hydrolyze ATP released on coexocytosis with acetylcholine via an ectonucleoside triphosphatase activity that is different from known endogenous nerve terminal ATPases. The final product of the hydrolysis, adenosine, can then be salvaged by the nerve terminal for resynthesis of ATP. Other possible physiological functions of the ectonucleotidases are discussed.
J Neurochem 1986 Sep
PMID:Ectonucleotidase activities associated with cholinergic synaptosomes isolated from Torpedo electric organ. 301 88

A plasma membrane fraction, highly enriched in 5'-nucleotidase activity, was prepared from human neutrophils by disruption of previously formed neutrophil cytoplasts (enucleated neutrophils), which were devoid of intracellular organelles. This plasma membrane fraction shows an extremely low contamination by specific and azurophilic granule markers as compared to previous reported preparations. Nevertheless, a novel tertiary granule (Mollinedo, F. and Schneider, D.L. (1984) J. Biol. Chem. 259, 7143-7150), unlike specific and azurophilic granules, fuses partially with the cell surface under the experimental conditions used for cytoplast preparation. Comparison between the external cell-surface proteins in resting neutrophils and neutrophil cytoplasts by lactoperoxidase-catalyzed iodination showed some differences both in deletion and in addition of proteins. In resting cells, iodine was incorporated into at least 13 proteins ranging in size from over 200 to 30 kDa. A 140 kDa polypeptide, representing the major labeled surface component in resting neutrophils, was absent from cytoplasts. Furthermore, high-molecular-weight proteins (110 and over 160 kDa were more exposed to iodination after cytoplast preparation. Activation of human neutrophils by N-formylmethionylleucylphenylalanine induced some alterations in the pattern of labeled cell-surface proteins, which correlated to a certain degree with those observed during cytoplast preparation.
Biochim Biophys Acta 1986 Sep 25
PMID:Isolation of human neutrophil plasma membranes employing neutrophil cytoplasts and changes in the cell-surface proteins upon cell activation. 301 98

The molecular layer of the cerebellar cortex contains high levels of the enzyme 5'-nucleotidase (EC 3.1.3.5), localized predominantly to Bergmann glia. In the present study, histochemical methods have been employed to examine the distribution of cerebellar 5'-nucleotidase in mice of two separate mutant strains in which Purkinje cells are eliminated selectively. In homozygous 'Purkinje cell degeneration' (pcd) and 'nervous' (nr) mice, molecular layer 5'-nucleotidase is greatly reduced and residual enzyme activity in colocalized with surviving Purkinje cells. These results suggest strongly that the expression of 5'-nucleotidase activity by Bergmann glia is under the inductive influence of their associated Purkinje cells.
Brain Res 1986 Sep
PMID:5'-Nucleotidase of cerebellar molecular layer: reduction in Purkinje cell-deficient mutant mice. 301 84

Chronic feeding of male Wistar rats with food containing hexachlorobenzene (HCB) at 17.5 mmol/kg induced elevation of serum amino-transferases and bilirubin content, increase of microsomal cytochrome P-450 concentration, and decrease of 5'-nucleotidase, K+,Na+- and Mg2+-adenosine triphosphatase activities in liver plasma membrane preparations. These changes were potentiated by ethanol consumption suggesting a possible role of liver plasma membrane damage in the pathogenesis of HCB intoxication.
Toxicol Lett 1986 Sep
PMID:Rat liver plasma membrane damage in hexachlorobenzene intoxication and its potentiation by ethanol. 302 30


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