Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.25 (triphosphatase)
 1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A microsomal fraction from ox cerebral cortex catalysed [(14)C]ADP-ATP exchange at a speed similar to that at which it liberated P(i) from ATP in the presence of Na(+), K(+) and Mg(2+). 2. Repeated washing the fraction with MgATP solutions solubilized most of the exchange activity and left the adenosine triphosphatase insoluble and little changed in activity. The exchange activity was accompanied by negligible adenosine-triphosphatase activity and was enriched by precipitation at chosen pH and by DEAE-Sephadex. At no stage was its activity affected by Na(+), K(+) or ouabain. 3. The washed microsomal fraction was exposed to a variety of reagents; a sodium iodide-cysteine treatment increased both adenosine-triphosphatase and exchange activities, as also did a synthetic zeolite. Preparations were obtained with exchange activities less than 3% of their Na(+)-plus-K(+)-stimulated adenosine-triphosphatase activity. Some contribution to the residual exchange activity was made by an adenylate kinase. 4. Thus over 95% of the microsomal ADP-ATP-exchange activity does not take part in the Na(+)-plus-K(+)-stimulated adenosine-triphosphatase reaction. Participation of some of the residual 3% of the ADP-ATP-exchange activity has not been excluded, but there appears no firm evidence for its participation in the adenosine triphosphatase; the bearing of this conclusion on mechanisms proposed for the Na(+)-plus-K(+)-stimulated adenosine triphosphatase is indicated.
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PMID:Separation of adenosine diphosphate--adenosine triphosphate-exchange activity from the cerebral microsomal sodium-plus-potassium ion-stimulated adenosine triphosphatase. 422 77

The reasons underlying reported discrepancies in the effects of ATP, ADP, adenosine 5'-[beta gamma-methylene]triphosphate, AMP + PPi, P-chloromercuribenzoate and F- on RNA efflux from isolated rat liver nuclei and on nuclear envelope nucleoside triphosphatase activity were investigated. The stimulatory effect of ADP was attributed to myokinase activity associated with the nuclei; this activity was eluted on repeated washing with nuclear incubation medium. In the absence of Ca2+ and Mn2+, ATP, adenosine 5'[beta gamma-methylene]triphosphate and AMP +PPi were found to promote release of both DNA and RNA. In the presence of 0.5 mM-Ca2+ and 9.3 mM-Mn2+, only ATP promoted RNA efflux to a significant extent. In the absence of spermidine, Ca2+ and Mn2+, nuclei released large quantities of DNA and RNA into the medium; this effect was promoted by p-chloromereuribenzoate. In the presence of the three cations, however, p-chloromercuribenzoate inhibited RNA efflux. F- caused a slight leakage of DNA from nuclei. The results are discussed in terms of models for the effects of ATP and analogues on RNA efflux and nuclear stability.
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PMID:Influence of nucleotides, cations and nucleoside triphosphatase inhibitors on the release of ribonucleic acid from isolated rat liver nuclei. 615 91

5'-Nucleoside triphosphates (NTP) are present in the liquid covering airway surfaces and mediate important physiologic events through their interaction with P2-nucleotide receptors. Activation of airway P2Y(2) receptors, for example, stimulates ciliary beat frequency, chloride/liquid secretion, and goblet cell degranulation. We, therefore, have studied the metabolic pathways that regulate the concentration of nucleotides on airway surfaces. Stimulation of submucosal gland secretion in the nose was previously found to decrease the concentration of 5'-adenosine triphosphate (ATP) in nasal lavage samples due to the presence of a secreted 5'-nucleoside triphosphatase (NTPase). In this study, gland secretions were further studied and found to also contain adenylate kinase (AK) and nucleoside diphosphokinase (NDPK) activities. Ecto-AK and ecto-NDPK activities were also detected in well-differentiated cultures of superficial nasal epithelia, which reflected a combination of cell-associated and released (into culture media) AK and NDPK activities. This study demonstrates that "ecto-kinases" on airway surfaces (1) emanate from different enzyme families, including both AK and NDPK; (2) are expressed at superficial epithelial surfaces and in submucosal glands; and (3) may be important regulators of nucleotide concentrations on airway surfaces.
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PMID:Secreted and cell-associated adenylate kinase and nucleoside diphosphokinase contribute to extracellular nucleotide metabolism on human airway surfaces. 1180 72

Campbell, J. J. R. (The University of British Columbia, Vancouver, B.C., Canada), Loretta A. Hogg, and G. A. Strasdine. Enzyme distribution in Pseudomonas aeruginosa. J. Bacteriol. 83:1155-1160. 1962.-Previous studies on the distribution of enzymes in bacteria have indicated that, although individual enzymes were predominantly associated with a particular cellular structure, nevertheless some of the enzyme appeared to be present in all cellular fractions. In the present work with Pseudomonas aeruginosa, it was shown that, in general, an enzyme is present in only one cellular component. Hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, gluconic dehydrogenase, malic dehydrogenase, fumarase, isocitric dehydrogenase, isocitritase, and catalase were detected only in the soluble cytoplasm of the cell. Glucose oxidase and succinic dehydrogenase were detected only in the "ghost" fraction. Diphosphopyridine nucleotide oxidase was present in both "ghost" and ribosomal fractions but was most concentrated in the "ghost". Although adenylic kinase was found to be present in all fractions, it was possible to fractionate cells so that almost all of the activity was associated with the soluble cytoplasm a minor amount being associated with the "ghost." Adenosine triphosphatase was most concentrated in the "ghost" but appreciable activity appeared in the cytoplasm. Polynucleotide phosphorylase appeared to be the only enzyme that was convincingly associated with the ribosomes. However, a small amount of activity was associated with the soluble cytoplasm and with the "ghosts."
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PMID:Enzyme distribution in Pseudomonas aeruginosa. 1387 40