Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microsomal fractions from homogenates of pig gastric fundic mucosa showed high levels of K+-stimulated adenosine triphosphatase (ATPase) and K+-stimulated phosphatase. Similar preparations from antral mucosa showed virtually no such activity. Because of mitochondrial contamination the fundic microsomes were further separated by sucrose density gradient centrifugation. A low density band of membranes (peak 1.12 to 1.13 g per ml) possessed all of the K+-stimulated enzyme activities. Morphological features and the abundant glycoproteins of the low density microsomes suggested they might be derived from the tubulovesicles of oxyntic cells. Mitochondrial and ribosomal markers were associated with membranes with much higher densities (greater than 1.22). The K+-stimulated ATPase has a pH optimum of 7.5 and required Mg++, but neither Na+ nor ouabain had any appreciable effect on the activity. Stimulation of basal ATPase by K+ ranged from 1.5 to 3.0-fold with an apparent Ka for activation between 0.2 to 0.4 mM K+. Addition of various K+ ionophoretic substances (e.g., gramicidin) produced further stimulation of K+-ATPase up to 6 times the basal rate. The mean activities for seven separate preparations of purified low density pig fundic microsomes were as follows (micromoles of ATP hydrolyzed per mg protein per hr +/- SEM); basal ATPase, 15.8 +/- 2.8; plus 10 mM K+, 29.3 +/- 4.5; plus 10 mM K+ and 10(-5) M gramicidin, 45.2 +/- 5.2. Neither the basal ATPase nor the K+-stimulated rates were altered by HCO3- or Cl-. The occurrence of these active and unique enzyme activities in the oxyntic region of gastric mucosa suggest some relation with secretory activity. Possible functional roles are discussed.
 ...
PMID:Unique enzymes of purified microsomes from pig fundic mucosa. K+-stimulated adenosine triphosphatase and K+-stimulated pNPPase. 23 96

Phosphatase activity was demonstrated in the lingual glands of man and dog. Especially the ducts of the glandular elements of the dog exhibited a peculiar and rather perplexing pattern of activity which does not seem to fit in with any of the prevailing concepts of the function of the duct system. The secretory capillaries (Sekretionscapillaren) in many of the serous acini of the human lingual glands have demonstrated phosphatase activity with all the 17 substrates used. The significance of these phosphatases, expecially ATPase, in the active transport across biological unit membranes has been discussed.
 ...
PMID:Phosphatases in the lingual glands of man and dog. 24 83

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
 ...
PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

A magnesium-independent deoxyuridine-5'-triphosphatase was found in Yoshida sarcoma cells but not in normal rat liver. The phosphatase is specific for deoxyuridine 5'-diphosphate and deoxyuridine triphosphate, and its Km for deoxyuridine triphosphate is 2.7 X 10(-7) M. The enzyme was not inhibited by fluoride and required no divalent cations. Thus it differs from known nucleotide phosphatases. Deoxyuridine monophosphokinase, which is detectable in a crude extract of normal rat liver, could not be detected in an extract of Yoshida sarcoma cells. However, with hydroxylapatite column chromatography of the extract, a deoxyuridine 5'-monophosphate kinase activity as high as that in normal rat liver was found in fractions separated from the phosphatase activity. Thus the absence of detectable deoxyuridine 5'-monophosphate kinase activity in the crude extract of Yoshida sarcoma cells is due to the presence of this nucleotide phosphatase.
 ...
PMID:A new deoxyuridine-5'-triphosphatase in Yoshida sarcoma cells involved in deoxyuridine 5'-triphosphate metabolism. 85 39

The brains of 35 male Wistar rats weighing 250 g were histologically and histochemically examined after a chronic intoxication due to five-month exposure to carbon disulfide. Morphologically, myelin sheath disruptions within the longitudinal tract systems of the spinal cord, destructions of individual ganglion cells in all brain regions and elective parenchyma necroses in the frontal and parietal cerebral cortices were found. The histochemical assays for enzyme activities of monoamine oxidase, ATPase, glucose 6-phosphatase, acetylcholine esterase and succinic dehydrogenase in the entire central nervous system revealed values identical to those obtained for control animals. Only succinic dehydrogenase and acetylcholine esterase revealed focal reduction in activities within the elective parenchyma necroses. After twenty-week duration of experiments a moderate decrease in activities of arylsulfatases and glutamic dehydrogenase in the entire central nervous system was found. Eventual causes responsible for these changes are discussed.
 ...
PMID:Histological and histochemical studies on the rat brain under conditions of carbon disulfide intoxication. 92 88

In different intervals 220 patients were examined after a resection of the stomach with Billroth's second operation. 179 of them spoke about complaints of different degrees of severity. The cases in question were an early dumping syndrome in 83 patients, which, with the exception of 7 patients, could be removed by simple dietetic measures, such as the elimination of incompatible foodstuff. Again and again the symptoms could be evoked by provocation with it. The method described by Henley proved as correcting operation. Apart from a few exception the fitness for work was not restricted by Billroth's second operation. In shift work or severe physical work a change of the working place was striven for. The body-weight which was reduced already before the operation again increased after operation in 50%, but reached the normal only in 20%. Recidivation ulcera and anastomositis of a suture were rare findings. Stump gastritis is no own clinical picture. Also in this case in histologically still normal mucous membrane earlier histochemical changes develop in the sense of a chronic gastritis with a reduction of the adenosin triphosphatase, the acid tissue phosphatase and succinodehydrogenase.
 ...
PMID:[Billroth II. Surgery of the stomach]. 96 Aug 63

In the bilaterally growing DBD sensitive Yoshida tumours deformed nuclear divisions necrosis of the majority of the tumour and appearance of giant cells can be observed due to the single administration of the LD50 of the preparation. The histochemical activity of the LDH the activity alcalyc Adenosine triphosphatase and the nonspecific alcalyc phosphatase become negative while the acidic phosphatase's activity does increase after the administration of the LD25 of the preparation appearance of giant cells are very marked more than 60% of tumours cells are polynuction. The activity of the alcalyc ATP-ase and nonspecific phosphatase decrose's after a transitory increase and become negative while the acid phosphatase's activity increases. In the case of the DBD resistant tumours the morphological and histochemical alternations due to LD50 of the preparation are much slighter and their timecourse is shorter. No morphological and histochemical changes are observed after the administration of LD25 of the preparation.
 ...
PMID:[Cytomorphological and enzyme histological studies of bilaterally inoculated Dibromdulcit-sensitive and-resistent Yoshida tumors]. 101 92

We have used liposomes with incorporated pig kidney Na+,K(+)-ATPase to study vanadate sensitive K(+)-K+ exchange and net K+ uptake under conditions of acetyl- and p-nitrophenyl phosphatase activities. The experiments were performed at 20 degrees C. Cytoplasmic phosphate contamination was minimized with a phosphate trapping system based on glycogen, phosphorylase a and glucose-6-phosphate dehydrogenase. In the absence of Mg2+ (no phosphatase activity) 5-10 mM p-nitrophenyl phosphate slightly stimulated K(+)-K+ exchange whereas 5-10 mM acetyl phosphate did not. In the presence of 3 mM MgCl2 (high rate of phosphatase activity) acetyl phosphate did not affect K(+)-K+ exchange whereas p-nitrophenyl phosphate induced a greater stimulation than in the absence of Mg2+; a further addition of 1 mM ADP resulted in a 35-65% inhibition of phosphatase activity with an increase in K(+)-K+ exchange, which sometimes reached the levels seen with 5 mM phosphate and 1 mM ADP. The net K+ uptake in the presence of 3 mM MgCl2 was not affected by acetyl phosphate or p-nitrophenyl phosphate, whereas it was inhibited by 5 mM phosphate (with and without 1 mM ADP). The results of this work suggest that the phosphatase reaction is not by itself associated to K+ translocation. The ADP-dependent stimulation of K(+)-K+ exchange in the presence of phosphatase activity could be explained by the overlapping of one or more step/s of the reversible phosphorylation from phosphate with the phosphatase cycle.
 ...
PMID:Phosphatase activity and potassium transport in liposomes with Na+,K(+)-ATPase incorporated. 130 62

We have previously shown that tomato lectin binds specifically to the 60-90 kDa membrane glycoprotein of parietal cell tubulovesicles, the beta-subunit of the gastric H+/K(+)-ATPase (proton pump) [Callaghan, Toh, Pettitt, Humphris & Gleeson (1990) J. Cell Sci. 95, 563-576; Toh, Gleeson, Simpson, Mortiz, Callaghan, Goldkorn, Jones, Martinelli, Mu, Humphris, Pettitt, Mori, Masuda, Sobieszczuk, Weinstock, Mantamadiotis & Baldwin (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 6418-6422]. Here we have exploited this interaction for the development of a rapid single-step chromatography procedure for the purification of an active pig gastric proton pump complex. Initially, H+/K(+)-ATPase-enriched membranes, prepared from pig gastric microsomes by density-gradient centrifugation, were extracted in 1% Triton X-100 and passed through a 1 ml tomato lectin-Sepharose 4B column. The bound material, eluted with 20 mM-chitotriose, showed a major band with an apparent molecular mass of 95 kDa, and a faint broad band of 60-90 kDa, by SDS/PAGE. N-Glycanase treatment of the bound material resulted in the appearance of a 35 kDa band, the size of the protein core of the 60-90 kDa glycoprotein beta-subunit. The two components were identified as the 95 kDa alpha-subunit and the 60-90 kDa beta-subunit of the gastric H+/K(+)-ATPase, by immunoreactivity with monospecific antibodies, and by tryptic peptide sequences of the tomato-lectin-bound material. The beta-subunit was present in approximately equimolar amounts to the catalytic alpha-subunit. Whereas the gastric H+/K(+)-ATPase was not active after solubilization in 1% Triton X-100, solubilization of density-gradient-purified membranes in the non-ionic detergent, C12E8, followed by chromatography of the extract on tomato lectin-Sepharose 4B, resulted in the purification of the gastric H+/K(+)-ATPase complex which exhibited K(+)-dependent phosphatase activity. This is the first report of a rapid purification of a partially active solubilized gastric H+/K(+)-ATPase complex.
 ...
PMID:Rapid purification of the gastric H+/K(+)-ATPase complex by tomato-lectin affinity chromatography. 131 70

Some modified cerium-based and Gomori-based cerium methods for the demonstration of phosphatase activity in cryostat sections were described. Dextrane as stabilizing agent was added to the incubation media for ATPase, 5'-Nase, and TPPase. The oxidation of the CeIII-phosphate primary reaction product in a separate step by H2O2 before the DAB incubation yielded an increase of the intensity of the DAB-based visualization reaction (Ce-H2O2-DAB-Ni two step method). The sensitivity of the histochemical enzyme reaction was remarkably increased if CeIII-ions were employed as amplifying agent (Ce/Ce-H2O2-DAB-Ni two-step method). A new suitable DAB medium consisting of 0.015% DAB, 2.0% Ni-sulphate, 15% methanol, and 0.005% H2O2 in 0.1 mol/l acetate buffer, pH = 5.2, was used. The disadvantage of diffuse background staining has been overcome by addition of 15% methanol to the DAB solution. Electrovalently bound CeIII (cerophilia) was removed by treatment of the incubated sections with CeIII-citrate (CeIII-complexation). In addition, a novel membrane floating incubation for sections is proposed. At present, the modified procedures are some of the most sensitive modes for the demonstration of phosphatases and improve the earlier described cerium-DAB one-step technique (Halbhuber et al. 1988b).
 ...
PMID:Modified cerium-based and Gomori-based cerium methods for light microscopic phosphatase histochemistry: the cerium-perhydroxide-diaminobenzidine-nickel (Ce-H2O2-DAB-Ni and Ce/Ce-H2O2-DAB-Ni) two-step procedures. 131 35


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>