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)

Some properties and subcellular localization of adenosine diphosphatase (ADPase) activity from rat heart have been investigated. The pH optimum was 7.4, maximal activity was found with 5 mM MgCl2, and the apparent Km was 20 microM. ADPase activity was strongly inhibited by NaF and AppNHp, and to a lesser extent by AMP and GppNHp. The enzyme was not inhibited by p-nitrophenylphosphate, beta-glycerophosphate, or pyridoxal phosphate. The distribution of ADPase activity in subcellular fractions obtained by differential centrifugation parallel ouabain-sensitive (Na+-K+)ATPase and 5'-nucleotidase activities, suggesting a plasma membrane-bound localization. The functional significance of ADPase in adenosine production and hemostasis is discussed.
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PMID:Properties and subcellular localization of adenosine diphosphatase in rat heart. 608 40

Using electron microscope cytochemistry and cells separated on Ficoll-Hypaque, Mg2+-dependent ATPase, ADPase and 5'-nucleotidase were predominantly localized as ectoenzymes on normal human granulocytes. Large deposits of ATPase final reaction product and more finely granular deposits of 5'-nucleotidase final reaction product were firmly attached to the outer surface of cell plasma membranes. The final reaction product from ecto-ADPase was, however, only loosely associated with the plasma membrane. In addition, finer deposits of ADPase final reaction product were seen in specific granules and in background cytoplasm. No nucleotidase phosphatase activity was localized to the alkaline phosphatase-containing granules (phosphasomes) recently described by Rustin et al. In granulocytes from patients with chronic granulocytic leukaemia, ecto-ATPase had a patchy distribution on the plasma membranes. There was considerable heterogeneity between cells with regard to ADPase and 5'-nucleotidase localization. In some cells, ADPase was seen only at both site, while in some cells no activity was detected. 5'-Nucleotidase localization was normal in some cells but lacking from many. No correlation was found between enzyme heterogeneity and the degree of morphological cell maturity.
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PMID:Electron microscopic cytochemical localization of nucleoside phosphatases in normal and chronic granulocytic leukaemic human neutrophils. 611 13

Specific assays for 5'-nucleotidase, adenosine diphosphatase (ADPase) and Mg2+-dependent adenosine triphosphatase (Mg2+-ATPase) have been optimized for human lymphocytes and their subcellular localizations determined by sucrose density gradient centrifugation. 5'-Nucleotidase was localized solely to the plasma membrane of the lymphocyte. ADPase activity has been shown to have a dual localization to the plasma membrane and mitochondria, whilst Mg2+-ATPase was mainly located in the mitochondria. No [Na+,K+] activated Mg2+-dependent ATPase could be measured in these cells. We have confirmed the striking decrease in the specific activity of 5'-nucleotidase activity in lymphocytes from patients with common variable primary hypogammaglobulinaemia. In contrast, the specific activities of ADPase and Mg2+-ATPase showed no alteration in lymphocytes from the patient group when compared to controls. Thus the deficiency of ecto-5'-nucleotidase in the lymphocytes of patients with hypogammaglobulinaemia is a highly selective defect in purine metabolism.
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PMID:Studies on the kinetic properties and subcellular localization of adenine nucleotide phosphatases in peripheral blood lymphocytes from control subjects and patients with common variable primary hypogammaglobulinaemia. 612 80

Enzyme cytochemical and immunocytochemical techniques at the light and electron microscope levels were used to study the distribution of potential markers of chemical transformation in rodent bladders. In rat tumours induced by in vivo treatment with methylnitrosourea, alkaline phosphatase localization was normal on the external surface of the plasma membranes of some cells but abnormal in others where reaction product was seen only on intracellular membranes. 5'-Nucleotidase localization was abnormal in all cells, being seen on endoplasmic reticulum and nuclear membranes only, while in normal bladders only ectoenzyme localization was seen. Heterogeneity of alkaline phosphatase amd 5'-nucleotidase localization was seen on the plasma membranes of these tumours after 15 days in organ culture. Some cells produced enzyme and others did not; in other cells only parts of the membrane reacted heavily, while other regions were negative. In transformed cell cultures and tumours of mouse bladder derived by in vitro treatment of explants with dimethylbenz (a) anthracene, a bimodal pattern of alkaline phosphatase localization was seen. Cells had either normal ectoenzyme reaction product or abnormal intracellular membrane reaction product. 5'-Nucleotidase and ADPase were lost after transformation while cAMP-phosphodiesterase was retained as an ectoenzyme. Mg.ATPase and a cAMP-independent, calcium-insensitive 'protein phosphatase' were induced in transformed cell cultures. An epithelial antigen was detected in the cytoplasm of both normal and transformed cells associated with reticular cytoplasmic ground substance, plasma membrane vesicles and cytoskeletal elements.
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PMID:Cytochemical markers of bladder carcinogenesis. 627 42

The properties and subcellular localization of adenosine diphosphatase (ADPase) activity in smooth muscle cells cultured from pig aortas have been investigated. The pH optimum of ADPase activity was 7.3 and the apparent Km for ADP was 10.3 microM. ADPase activity was inhibited completely by EDTA and was restored by the addition of divalent cations. The enzyme activity was not inhibited by 2-glycerophosphate, a substrate for non-specific phosphatases, nor by levamisole, a specific inhibitor of alkaline phosphatase. Smooth muscle cells were homogenized and a post-nuclear supernatant was applied to a sucrose density gradient in a Beaufay automatic zonal rotor. The distribution of ADPase activity in the density gradient was similar to that of 5'-nucleotidase activity, a marker enzyme for the plasma membrane, and distinct from the distributions of the marker enzymes for the other organelles. When the cells were homogenized in the presence of digitonin, an agent which binds to cholesterol and increases the equilibrium density of the plasma membrane, the modal equilibrium densities of ADPase activity and of 5'-nucleotidase activity were increased to similar extents, thus confirming the plasma membrane localization of ADPase activity.
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PMID:Properties and subcellular localization of adenosine diphosphatase in arterial smooth muscle cells in culture. 629 83

By means of DEAE-Sephadex A-50 column chromatography and gel filtrations on Sephadex G-75, Sephacryl S-300 and Sephadex G-100, successively, a potent 5'-nucleotidase was purified from Trimeresurus gramineus venom. The venom 5'-nucleotidase is a single polypeptide chain and homogeneous as judged by SDS-polyacrylamide gel electrophoresis. It is a thermostable glycoprotein consisting of 589 amino acid residues. Its molecular weight was estimated to be 74,000 by SDS-polyacrylamide gel electrophoresis. It possessed nucleotidase activities toward adenosine monophosphate and adenosine diphosphate. The specific activities toward AMP and ADP were 504 +/- 28 and 101 +/- 8 micrograms Pi/min per mg, respectively. Pre-incubation of this venom's 5'-nucleotidase with ADP resulted in the cleavage of ADP and formation of adenosine. The 5'-nucleotidase activity was inhibited by EDTA. Both Zn2+ and Co2+/- reversed the inhibitory effect of EDTA. In rabbit platelet-rich plasma, it inhibited completely the ADP (2 x 10(-5) g/ml)-induced platelet aggregation. It also inhibited the platelet aggregations induced by sodium arachidonate (100 microM), collagen (20 micrograms/ml) and ionophore A-23187 (5 microM)-induced platelet aggregations were not affected significantly by this venom 5'-nucleotidase. In ADP-refractory platelet-rich plasma, the venom 5'-nucleotidase inhibited the platelet aggregations induced by collagen (20 micrograms/ml) or sodium arachidonate (100 microM). The venom 5'-nucleotidase showed a more pronounced inhibitory effect on sodium arachidonate-induced platelet aggregation than creatine phosphate/creatine phosphokinase and apyrase did. No lactate dehydrogenase was released by this venom 5'-nucleotidase, indicating that no platelet lysis occurred. It is concluded that removal of ADP, which is released by these platelet aggregation inducers, and the subsequent accumulation of adenosine are responsible for the inhibitory effect of the venom 5'-nucleotidase on platelet aggregations.
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PMID:Inhibition of platelet aggregation by 5'-nucleotidase purified from Trimeresurus gramineus snake venom. 631 33

Twenty eight enzymatic activities and four macromolecular substances have been histochemically compared in rat and rabbit aortas, embedded in a common block. The study was carried out at different stages of development: 3 days, 3 months, 7-9 months and 17-19 months. In addition, lipase and cholinesterase were biochemically assayed in adult rat and rabbit aortas. The rat aortas (atheroresistant) had a better supply of aerobic oxidoreductases [linked to the pentose pathway (G6PD, 6PGD) as well as to the Krebs cycle (SD, ICD)], lipolytic enzymes (acid esterases, cholinesterase, lipase), lysosomal enzymes (acid PH/ase, Aryl-sulf/ase - Betaglu/ase), ADPase - ATPase - AlK Ph/ase Alpha GPD and acid lipids. Rabbit aortas (atherosensitive) were richer in metachromatic GAG, UDPGD (GAG Anabolism), glycogen, and related enzymes (phosphorylase, glycogen synthetase) as well as 5'-nucleotidase, Beta HBD, Lactate D and Aldolase. These differences support the hypothesis that arterial atherosensitivity is related to the activity and efficiency of smooth muscle cell energetic and catabolic processes, which govern the behaviour of lipids, proteins and carbohydrates as they penetrate the arterial wall. The factors that determine the proliferative and sclerogenic responses of arterial tissues to aggressions and, in particular, the response to lipids, remain, however, to be determined.
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PMID:A comparative study of the arterial tissue metabolism in atherosensitive and atheroresistant species. I. Comparison between rabbit and rat aortas. 734 89

A method for the visualization of the ecto-nucleotidase enzyme activities present on the cell surface, employing 141Ce3+ as a capturing and labelling agent, is described. Phosphate ions precipitated at the cell surface can be detected by coating the cells with an autoradiographic emulsion, followed by light microscopical inspection of the formed silver grains. The activities of ecto-ATPase, ecto-ADPase and 5'-nucleotidase were detected by this approach in four different cell lines. Parallel biochemical measurements of the activities of the corresponding enzymes were carried out in order to validate, evaluate, and optimize the cytochemical detection. The finding that Ce3+ ions are inhibitory to ecto-ATPase provided evidence for the necessity of carefully establishing appropriate reaction conditions for the cytochemical determination of ecto-nucleotidases. The application of this method to the indirect detection of extracellular adenosine production from substrates like ATP has also been documented. It allows a cytochemical determination of adenosine formed through cascade nucleotide dephosphorylation. This newly described method is of high sensitivity and potentially of value for a variety of applications, including not only cytochemistry but also cell biology, and molecular biology studies.
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PMID:Autoradiography-based cytochemical detection of ecto-ATPase, ecto-ADPase, 5'-nucleotidase, and extracellular adenosine production, employing 141Ce3+ as a capturing agent. 759 48

The components of the ectonucleotidase pathway at the immunoaffinity-purified striatal cholinergic synapse have been studied. The ecto-ATPase (EC 3.6.1.15) had a Km of 131 microM, whereas the ecto-ADPase (EC 3.6.1.6) had a Km of 58 microM, was Ca(2+)-dependent, and was inhibited by the ATP analogue 5'-adenylylimidodiphosphate (AMPPNP). The ecto-5'-nucleotidase (EC 3.1.3.5) had a Km of 21 microM, was inhibited by AMPPNP and alpha,beta-methylene ADP, and by a specific antiserum. The Vmax values of the ATPase, ADPase, and 5'-nucleotidase enzymes present at this synapse were in a ratio of 30:14:1. Very little ecto-adenylate kinase activity was detected on these purified synapses. The intraterminal 5'-nucleotidase enzyme, which amounted to 40% of the total 5'-nucleotidase activity, was inhibited by AMPPNP, alpha,beta-methylene ADP, and the antiserum, and also had the same kinetic properties as the ectoenzyme. The time course of ATP degradation to adenosine outside the nerve terminals showed a delay, followed by a period of sustained adenosine production. The delay in adenosine production was proportional to the initial ATP concentration, was a consequence of feedforward inhibition of the ADPase and 5'-nucleotidase, and was inversely proportional to the ecto-5'-nucleotidase activity. The function and characteristics of this pathway and the central role of 5'-nucleotidase in the regulation of extraterminal adenosine concentrations are discussed.
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PMID:Production of adenosine from extracellular ATP at the striatal cholinergic synapse. 841 43

Salivary gland homogenates of Culicoides variipennis, the primary vector of bluetongue (BLU) viruses in North America, were analyzed for apyrase activity. Apyrase (ATP diphosphohydrolase, EC 3.6.1.5) is an anti-hemostatic and anti-inflammatory salivary enzyme of most hematophagous arthropods. The enzyme activity was measured by the release of orthophosphate using ATP, ADP, and AMP as substrates with Ca2+ as the divalent cation. ATPase (11.5 +/- 1 mU/pair of glands), ADPase (7.3 +/- 0.7 mU/pair of glands), and insignificant (P < 0.05) AMPase (0.07 mU/pair of glands) activities were detected in female salivary glands. Male salivary glands contained lower amounts of ATPase and ADPase activity (P < 0.05). The ATPase and ADPase activities were greatest at pH 8.5, and were similarly activated by Mg2+. Molecular sieving HPLC of salivary gland homogenates generated a single peak which coincided with ATPase and ADPase, but no AMPase, activity; the protein has an estimated molecular mass of 35,000 Da. ATPase and ADPase activity, and total protein concentration, were reduced (P < 0.05) in the salivary glands of females after taking a blood meal from a sheep. Salivary gland homogenates also inhibited ADP-induced platelet aggregation in vitro. It is concluded that the salivary ATPase and ADPase activities of C. variipennis reside in one enzyme, and that this enzyme is likely an apyrase. The apyrase activity is thought to be responsible for the inhibition of ADP-induced platelet aggregation, as indicated by the apparent discharge of apyrase from salivary glands into the host during blood feeding. This suggests that apyrase is one of the salivary proteins present in C. variipennis acting as antigens in the development of Culicoides hypersensitivity in ruminants and horses. Apyrase may inhibit an inflammatory response at the feeding site through the subsequent degradation of its end-product, AMP, to adenosine, a potent anti-inflammatory substance, by the ecto-5' nucleotidase activity of neutrophils.
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PMID:Apyrase activity and adenosine diphosphate induced platelet aggregation inhibition by the salivary gland proteins of Culicoides variipennis, the North American vector of bluetongue viruses. 872 May 70


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