5′‐Nucleotidase from the electric ray electric lobe

Volknandt, Walter; Vogel, Manfred; Pevsner, Jonathan; Misume, Yoshio; Ikehara, Yukio; Zimmermann, Herbert

doi:10.1111/j.1432-1033.1991.tb16443.x

Cited by 51 publications

(33 citation statements)

References 39 publications

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“…4). The putative protein displayed conservation in location and spacing of all seven domains known to be present in enzymes exhibiting 5'-nucleotidase activity (20). Furthermore, amino acid differences in the domains result principally from conservative changes at the nucleotide and amino acid level (for example, multiple substitutions of isoleucine for leucine and valine).…”

Section: Resultsmentioning

confidence: 99%

“…Most striking is the absence of a hydrophobic carboxylterminal domain in the mosquito protein. This region is present in the 5'-nucleotidase family and is the one that is substituted for a glycosylphosphatidylinositol (GPI) membrane-anchoring moiety during posttranslational modification (20)(21)(22). The mosquito apyrase does have the conserved serine residue (aa 559) to which the GPI anchor is attached covalently in the 5'-nucleotidases.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

The salivary gland-specific apyrase of the mosquito Aedes aegypti is a member of the 5'-nucleotidase family.

Champagne

Smartt

Ribeiro

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

225

171

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The saliva of hematophagous insects contains a variety of pharmacologically active substances that counteract the normal hemostatic response to injury in vertebrate hosts. The yellow-fever mosquito, Aedes aegypti, secretes an apyrase that inhibits ADP-dependent platelet aggregation. Apyrase was purified as an active enzyme from adult female salivary glands and subjected to tryptic digestion, and the resulting peptides were sequenced. The amino acid sequences obtained match the conceptual translation product of a cDNA clone isolated from an adult female salivary gland library. Sequence comparisons indicate similarities with a ubiquitous family of 5'-nucleotidases. The mosquito protein differs from other members of the family by lacking a carboxyl-terminal hydrophobic domain. The apparent conversion of a gene encoding an enzyme involved in a common metabolic event at the cellular level to a gene involved in the antihemostatic response of mosquitoes illustrates one way this particular insect has adapted to the challenges of bloodfeeding.The name apyrase (ATP diphosphohydrolase, EC 3.6.1.5) was first used by Meyerhof (1) to describe a yeast enzyme that hydrolyzed the pyrophosphate bonds of nucleoside di-and triphosphates. Apyrase activity was found also in vertebrate tissues, but the existence of apyrase was challenged when Kalckar (2) showed that the activity in muscle resulted from the concerted action of an ATPase and adenylate kinase. However, true apyrase activity was purified to apparent homogeneity from plants, especially potato tubers and pea cotyledons (3), and more recently, apyrase has been recognized in a variety of vertebrate tissues (4-6) and in the salivary secretions of many hematophagous insects (7,8). The functional significance of most of these enzymes remains unknown, but insect salivary apyrases inhibit platelet aggregation by destroying adenosine di-and triphosphates released from injured cells or by activated platelets.The secreted salivary apyrase of the mosquito Aedes aegypti shares a number of similarities with vertebrate pancreatic and endothelial apyrases, including molecular weight, pH sensitivity, divalent cation dependence, and immunological crossreactivity (9). However, the gene family to which this enzyme belongs was previously unknown. In this report, the salivary apyrase of A. aegypti is characterized as a member of the 5'-nucleotidase gene family.1 MATERIALS AND METHODS Mosquitoes. Adult mosquitoes (A. aegypti, Rockefeller strain) were reared in a 27°C controlled environment room at 80% relative humidity with a 16 hr light/8 hr dark cycle. All animals used in these experiments were 2-to 7-day-old adult females. Mosquitoes were fed a 10% sucrose solution.Purification, Activity, and Peptide Sequencing of Salivary Gland Apyrase. Salivary glands from adult female A. aegypti mosquitoes were dissected in phosphate-buffered saline (PBS), transferred to 10 mM Tris (pH 7.5), and stored frozen at -80°C. To purify active apyrase, 100 pairs of glands were homogenized with a Branson So...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The salivary gland-specific apyrase of the mosquito Aedes aegypti is a member of the 5'-nucleotidase family.

Champagne

Smartt

Ribeiro

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

225

171

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“…General molecular properties EN was first cloned from rat [237], human placenta [238], and the electric ray Torpedo electric organ [239], followed by identification of the cDNA sequence of a considerable variety of mammalian species [202,240]. The human cDNA encodes a precursor of 574 residues that is converted to the mature form of 523 residues after cleavage of the signal peptide and the hydrophobic domain at the C-terminus, which is replaced with the GPI anchor, similar to the enzymes cloned from rat [237] and mouse [204].…”

Section: Ecto-5′-nucleotidase Versus Soluble 5′-nucleotidasesmentioning

confidence: 99%

Cellular function and molecular structure of ecto-nucleotidases

Zimmermann

Zebisch

Sträter

2012

Purinergic Signalling

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890

922

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Ecto-nucleotidases play a pivotal role in purinergic signal transmission. They hydrolyze extracellular nucleotides and thus can control their availability at purinergic P2 receptors. They generate extracellular nucleosides for cellular reuptake and salvage via nucleoside transporters of the plasma membrane. The extracellular adenosine formed acts as an agonist of purinergic P1 receptors. They also can produce and hydrolyze extracellular inorganic pyrophosphate that is of major relevance in the control of bone mineralization. This review discusses and compares four major groups of ectonucleotidases: the ecto-nucleoside triphosphate diphosphohydrolases, ecto-5′-nucleotidase, ecto-nucleotide pyrophosphatase/phosphodiesterases, and alkaline phosphatases. Only recently and based on crystal structures, detailed information regarding the spatial structures and catalytic mechanisms has become available for members of these four ecto-nucleotidase families. This permits detailed predictions of their catalytic mechanisms and a comparison between the individual enzyme groups. The review focuses on the principal biochemical, cell biological, catalytic, and structural properties of the enzymes and provides brief reference to tissue distribution, and physiological and pathophysiological functions.

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“…A BLAST search using this sequence indicated high levels of similarity with mammalian and insect 5Ј-nucleotidases. Enzymes in the 5Ј-nucleotidase family are characterized by five to seven conserved sequence regions (58), and indeed the N-terminal sequence of the T. spiralis protein contains one of these regions, which is considered a 5Ј-nucleotidase signature (LTLIHTND). A search of the T. spiralis EST database using the N-terminal protein sequence indicated identity with an ORF from two overlapping cDNAs (GenBank accession numbers BG353625 and BG302003).…”

Section: Discussionmentioning

confidence: 99%

Nucleotidase Cascades Are Catalyzed by Secreted Proteins of the Parasitic NematodeTrichinella spiralis

Gounaris

2002

Infect Immun

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Extracellular nucleotides are signaling molecules whose receptor-mediated effects are involved in a variety of physiological responses in mammalian tissues. An overwhelming body of data indicate that inflammatory and other immune responses can be modulated by the availability and local concentrations of nucleotides via nucleotide receptor signaling, but this is only just beginning to be investigated in the context of infectious disease. Evidence is provided here that the parasitic nematode Trichinella spiralis can catalyze the conversion and thus modulate both the availability and concentration of extracellular nucleotides by means of the following secreted exoenzymes: apyrase, 5-nucleotidase, and adenosine deaminase. These enzymes were characterized in terms of substrate specificity, kinetic behavior, pH, divalent cation preferences, and response to a series of compounds. The secreted 5-nucleotidase was identified as a protein with an apparent molecular mass of 67 kDa after N-terminal amino acid sequencing of the purified protein. The presence of adenosine deaminase was confirmed in the secreted products by Western blotting with an antibody against a mammalian enzyme, as a protein with an apparent molecular mass of 38 kDa. These secreted proteins constitute an enzymatic cascade which catalyzes the degradation of extracellular nucleotides, with a potential physiological role in the regulation of purinergic signaling.Purinergic signaling relies on interactions between extracellular nucleotides and plasma membrane-bound receptors. This type of signaling therefore depends on nucleotide release, metabolism by enzymes acting extracellularly, and the presence of receptors which will selectively bind the resulting nucleotides and transduce the signal to the interior of the cell.Receptors for purine and pyrimidine nucleotides exhibit a wide tissue distribution including all hematopoietic cells (1,16,29,48), and numerous studies have demonstrated that extracellular nucleotides regulate a broad range of inflammatory and other immune responses (14,15,17,39,47). There is now clear evidence that nucleotides are released extracellularly in a regulated manner. In addition, large amounts of nucleotides are released upon mechanical stimulation (such as stretching) of different cell types, including epithelial and endothelial cells, and massive release of nucleotides into the extracellular space follows cell damage resulting in the activation of purinergic receptors (34,36,37,39,65). The latter are broadly divided into two categories, the P1 and the P2 receptors. P1 receptors respond specifically to adenosine (and some to inosine), whereas P2 receptors are responsive to ATP, UTP, ADP, and UDP (14, 48, 39). P1 receptors have been classified on the basis of biochemical and pharmacological properties into four G-protein coupled receptor subclasses, designated A 1 , A 2A , A 2B and A 3 . P2 receptors are subdivided into the G-protein coupled P2Y receptors and the ligand-gated ion channel P2X receptors. To date, seven mammalian P2X re...

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5′‐Nucleotidase from the electric ray electric lobe

Cited by 51 publications

References 39 publications

The salivary gland-specific apyrase of the mosquito Aedes aegypti is a member of the 5'-nucleotidase family.

The salivary gland-specific apyrase of the mosquito Aedes aegypti is a member of the 5'-nucleotidase family.

Cellular function and molecular structure of ecto-nucleotidases

Nucleotidase Cascades Are Catalyzed by Secreted Proteins of the Parasitic NematodeTrichinella spiralis

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