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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous freeze-fracture results from our laboratory have shown a reduction in a population of intramembrane particles in the lateral endothelial membranes from dysfunctional human corneas. The size range of these intramembrane particles corresponds to that which has previously been reported for the glycoprotein enzyme Na, K-ATPase in enzyme enriched freeze-fractured membranes. In order to investigate glycoconjugate changes potentially related to the particle reduction, wheat germ agglutinin (WGA), which has been shown to bind to the sugar residues in the ATPase subunit, was used to label three types of corneas with dysfunctional endothelial cells (Fuchs' endothelial dystrophy, aphakic and pseudophakic bullous keratopathy) and two types of corneas (eye bank and keratoconus) with functional endothelium using the technique of thin section freeze-fracture label. Apical WGA labelling on all types of dysfunctional cells was shown to be drastically reduced in comparison to both types of functional corneal endothelial cells. Lateral membranes of dysfunctional cells, exposed by freeze-fracturing, also showed a great reduction in WGA labelling as compared to the fractured lateral membranes of functional cells. The differences observed in lectin labelling of lateral membranes may be related in part to the decreased intramembrane particle density observed in dysfunctional human corneal endothelial cells.
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PMID:Freeze-fracture label of functional and dysfunctional human corneal endothelium. 358 77

Twenty-one cases (25 biopsies including 9 frozen biopsies) of Kaposi's sarcoma associated with the acquired immune deficiency syndrome (AIDS) were examined immunohistochemically, lectin-histochemically, and enzyme histochemically to ascertain the histogenesis of the lesion. The Kaposi's sarcomas were histologically subtyped according to a modified Schmid's classification (granulation tissue-like-, angiosarcoma-like- and spindle cell type). In almost all lesions, many atypical vasoforming cells and at least some spindle cells without definite evidence of vasoformation by conventional microscopy were positive for factor VIII-related antigen, BMA 120 (a new monoclonal antibody to an endothelial cell-specific antigen), Ulex europaeus I (UEA-I), alkaline phosphatase and ATPase. Linear reaction products for BMA 120 and UEA-I, suggesting the luminal surface of immature vascular channels, were sometimes recognized in the positive spindle cells. Electron micrographs confirmed endothelial characteristics, such as irregular and fragmented but distinct basal lamina and numerous pinocytotic vesicles, in both the UEA-I- and ATPase-positive spindle cells. Among spindle cells negative for the endothelial markers, there were many macrophages as a stromal reaction to tumor tissue, identified by monoclonal antibodies to macrophages (KiM 6, 7, 8 and EBM 11), acid phosphatase and alpha-naphthyl acetate esterase. The results of the immuno- and enzyme histochemical investigations did not correlate with the different histologic types of Kaposi's sarcoma. However, our results strongly suggest that tumor cells of Kaposi's sarcoma are derived from vascular endothelial cells rather than lymphatic endothelium.
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PMID:Histogenesis of Kaposi's sarcoma associated with AIDS: a histologic, immunohistochemical and enzyme histochemical study. 368 78

The existence of HLA-DR/Ia-like antigen (Ia)-bearing cells of the mononuclear phagocyte system, macrophages (Mac), and/or interdigitating cells (IDC), in the normal kidney is controversial. If present, such cells may be important in renal transplant rejection. We performed enzyme histochemistry using alpha-naphthyl acetate/butyrate esterases (alpha NAE, alpha NBE), 5'-nucleotidase (5'N), acid phosphatase (AcP), alkaline phosphatase (AlkP), and ATPase (ATP) as well as immunoperoxidase staining for Ia and lectin binding (Ulex europaeus I; UEA) on plastic-embedded tissue sections of normal kidneys and rejected renal allografts. Plastic embedding provides clear visualization of histologic detail and allows specific identification of immunoperoxidase-stained cells. Mac and IDC (shown to be Ia+, alpha NAE+, AcP+, ATP+ in other sites) could not be demonstrated in normal renal interstitium. IDC and Mac were not generally identified in normal mesangium, although they could not be altogether distinguished from Ia+ endothelial cells. Focal mesangial staining for alpha NAE but not alpha NBE was present. Rejected kidneys showed increased numbers of alpha NAE+ cells in glomeruli. These cells were frequently Ia negative and often appeared to be blood monocytes present in capillary lumens. Peritubular capillaries and glomerular endothelium stained strongly for UEA, 5'N, and Ia. Our results suggest that previous reports of the presence of IDC in renal tissue on the basis of staining for Ia on frozen tissue may be due to staining of compressed or obliquely sectioned vascular structures that were not adequately visualized.
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PMID:Monocyte/macrophage derived cells in normal and transplanted human kidneys. 389 Nov 75

Cytochemical localization of Concanavalin A binding sites in protoplasts of Candida tropicalis, investigated with glycosylated-ferritin and electron microscopy, showed that the lectin was specifically bound to the external protoplast surface. Thus, the plasma membranes have been labelled with 125I-Concanavalin A and followed through the isolation procedure. Relative distribution of 125I-radioactivity and azide-insensitive ATPase activity in the obtained fractions, suggested that this enzyme was an equivocal plasma membrane marker. Despite the presence of internal Concanavalin A binding sites, Concanavalin A could be used unambiguously as an exogenous plasma membrane marker of intact protoplasts.
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PMID:An investigation into the feasibility of using azide-insensitive ATPase and ConA as yeast plasma membrane markers. 612 37

Axenically propagated Entamoeba histolytica (HK9:NIH strain) were employed as starting material for the isoation of plasma membrane by a novel procedure. In the absence of known enzymatic markers, the externally disposed polypeptides of intact amoebae were iodinated and the incorporated label used to monitor membrane separation and recovery. 12 major plasma membrane polypeptides (12 x 10(3)-200 x 10(3) mol wt) were labeled and separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Each of these was a glycoprotein. Preincubation of amoebae with concanavalin A stabilized the plasma membranes as large sheets, facilitating its separation by low-speed centrifugation. Dissociation of the lectin with alpha-methyl mannoside, followed by additional homogenization led to vesiculation and further purification. The isolated plasma membrane was recovered in high yield (28%) and enriched 30-fold in terms of incorporated iodide. All iodinated surface glycoproteins of the intact organism were present in the plasma membrane fraction. A Ca++-dependent ATPase was enriched in the plasma membrane to a similar extent, but over one-half of the total activity was associated with internal, unlabeled membranes, suggesting a dual localization of this activity. The isolated plasma membrane was enriched in cholesterol and had a cholesterol:molar ratio of 0.87. It also contained larger amounts of an unusual phospholipid--ceramide aminoethyl phosphonate--a phospholipase-resistant species.
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PMID:Plasma membrane of Entamoeba histolytica. 624 83

High voltage free flow electrophoresis has been applied to the separation of human platelet membranes. After short treatment with neuraminidase at the whole cell level, three membrane vesicle subpopulations have been isolated. Using a surface label (125I-labeled Lens culinaris lectin), the marker enzyme NADH-cytochrome c reductase, and lipid analysis, two of the fractions have been identified as of surface origin and the other consists of intracellular membrane elements. The distribution of adenylate cyclase, leucyl aminopeptidase, 5'-nucleotidase and Ca2+-ATPase has also been investigated, and their usefulness as markers for the different membrane fractions has been evaluated. All three fractions are vesicular but differ in size and character. Their phospholipid and cholesterol contents have been determined, and the cholesterol/phospholipid ratios of the two surface fractions are over twice that of the intracellular membrane, which also has a significantly lower microviscosity as determined by fluorescence polarization using diphenyl hexatriene. The polypeptide profiles from sodium dodecyl sulfate-polyacrylamide gel electrophoresis are particularly distinctive, with actin present in the two surface membrane fractions and absent from the intracellular membranes. Myosin, confirmed by its ATPase characteristics, is almost exclusively localized in one of the surface membrane fractions, and actin-binding protein is a prominent feature of the other.
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PMID:Characterization of human platelet surface and intracellular membranes isolated by free flow electrophoresis. 626 Jul 85

Plasma membranes were isolated from C6 glioblastoma cells by two methods. In the first method cells were treated with concanavalin A and lysed in hypotonic medium. After partial separation of plasma membranes from other cell material, the lectin was displaced with alpha-methyl-D-mannoside. In the second method untreated cells or cells iodinated in a lactoperoxidase-catalyzed reaction were homogenized in isotonic medium. Membrane fractions obtained by either homogenization procedure were further purified by rate zonal and equilibrium centrifugations into linear density gradients. Disruption of the glioblastoma cell membrane gives rise to heterogeneous assemblies of membrane fragments. Two populations of plasma membranes were isolated from untreated and from iodinated cells: a "lighter" membrane fraction characterized by relatively lower sedimentation velocity and buoyant density, and a "heavier" membrane fraction of relatively faster sedimentation velocity and higher buoyant density. Both fractions showed electrophoretic patterns similar to those of 125I-labeled cell surface proteins. Their specific (Na+ + K+)-ATPase activity was seven- to eightfold the homogenate activity (recovery, 13.1%). Both fractions were, however, still contaminated by smooth endoplasmic reticulum, as judged from the activity of NADPH-dependent cytochrome c reductase (recovery, 2.4%). It is suggested that plasma membrane fragments present in the two fractions might differ in the organization of their structures, e.g., membrane vesicle intactness and membrane orientation.
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PMID:Isolation of cell surface membranes from cultured C6 glioblastoma cells. 628 63

The present investigation was directed toward answering the question of whether some age-related changes of membrane dependent triggering mechanisms during lymphocyte activation could account for the depressed T cell response to mitogens in aging. For this purpose, the K+ movements were analyzed in PHA-stimulated peripheral blood lymphocytes (PHA-PBL) from old humans (O) compared to adult (A). Indeed, plasma membrane Na+, K+, ATPase activation plays an essential role in cell proliferation and results from direct interaction between the loaded mitogen receptor and the enzyme. No difference could be found in the magnitude and the timing of the PHA-induced increase of K+ fluxes between PHA-PBL from O and A despite a higher K+ inflow in unstimulated but 20-hour preincubated PBL from O. Further experiments showed that the lectin-induced triggering mechanism of cation transport resulted from digoxine (DGX: a glycosid cardiotonic) sensitive ATPase. Moreover, whereas PBL from O exhibited a decreased PHA-induced DNA synthesis, DGX depressed the thymidine incorporation by 72-hour cultured PHA-PBL within the same inhibitory dose-related pattern in both O and A. We conclude that the triggering mechanism of Na+, K+-ATPase induced by PHA occurs adequately in early stimulated PBL from old subjects. In addition, digoxine sensitive structures work freely during PHA-induced lymphocyte proliferation in aging, thereby supporting further arguments for adequate Na+, K+-ATPase activity.
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PMID:Biochemical events associated with lymphocyte activation in aging. K+ transport and sensitivity of the Na+-K+ pump to digoxine. 629 41

Three techniques for the disruption/recovery of tegumental free-surface plasmalemma were compared by (i) morphological examination of carcasses and centrifugally-derived isolates, (ii) specific enrichment of bound surface tags (lectin) and of "marker" enzymes for membrane, and (iii) assessment of total protein and lectin recovered by each procedure. Procedures compared included the use of Triton X-100, freezing and thawing, and high ionic strength calcium. Triton X-100 consistently provided the greatest amounts of recovered surface membrane on a per worm basis, whereas calcium retained the highest amounts of alkaline p-nitrophenyl phosphatase, adenosine triphosphatase, and adenosine monophosphatase activity. Ultrastructural examination of membrane isolates and worm carcasses prepared by freezing and thawing indicated that significant amounts of parenchymal material contaminated the membrane fractions. Thus results based on the freeze-thaw technique can be difficult to interpret.
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PMID:Comparison of calcium, freeze-thaw, and Triton X-100 tegumental disruption/recovery techniques applied to Schistosoma mansoni. 631 92

(Na+,K+)ATPase from dog kidney was solubilized and denatured by SDS treatment, then applied to a Con A- and WGA-Sepharose column. While the alpha subunit of the ATPase had no affinity for either of the lectin-Sepharoses, the beta subunit specifically bound to WGA-Sepharose and was eluted with N-acetylglucosamine. This property was utilized for the isolation of the alpha and beta subunits by using lectin-Sepharoses and SDS-polyacrylamide gel electrophoresis. The amino acid composition of the alpha subunit thus isolated was in reasonable agreement with the data reported by Kyte (Kyte, J. (1972) J. Biol. Chem. 247, 7642-7649). The amino acid and carbohydrate compositions of the beta subunit were, however, different from his data. The beta subunit contained little histidine (0.1 mol/100 mol amino acid) and a very large amount of carbohydrates (33%). The antibody raised against alpha or beta subunit reacted specifically with the corresponding subunit and with protease-fragmented alpha subunit and neuraminidase-treated beta subunit, respectively, but no cross-reactivity was observed between the two subunits. These results indicate that our alpha and beta subunits were highly purified.
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PMID:Isolation of the alpha and beta subunits of canine (Na+,K+)ATPase by using SDS-PAGE and lectin-Sepharose. 632 83


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