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

---

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

Hepatocytes from rats were isolated by treatment with trypsin and cultured. Plasma membranes at different culture stages were observed by electron microscopy. The activities of 5' nucleotidase and adenosinetriphosphatase on the plasma membranes were examined. The cell coat was also studied by use of the concanavalin A-peroxidase technique. The surfaces of single cells, covered with microvilli, are the site of adenosinetriphosphatase activity only and are devoid of 5'-nucleotidase activity. After a few h of culture, the cells are grouped together in tight clusters or long trails and are separated by an intercellular space of 250 A, partially permeable to lanthanum nitrate. The juxtaposed plasma membranes on which 5'-nucleotidase and adenosinetriphosphatase activities occur also delimit spaces similar to bile canaliculi. The formation of junction complexes and their permeability to lanthanum nitrate was also studied. No enzymatic activity is observed at the junctions. The numerous tight junctions, impervious to the tracer, are always accompanied by a profusion of microfilaments. Mature desmosomes are rare, and are present only in the form of "maculae adhaerentes diminutae." The gap junctions, nearly always permeable to the tracer, form rapidly and assume a variety of shapes (trail, bulge and ring-like), the significance of which is open to discussion. The use of concanavalin A permits localization of the free sugar sites on the surface of the cells, in the pinocytotic vesicles and in the internal space of the gap junctions.
...
PMID:Differentiation of the plasma membrane of hepatic cells in monolayer cultures. 13 45

To determine whether choleretic infusions of bile acids modified the function or structure of the membrane of the bile canaliculus, sodium taurocholate (NaTc) or dehydrocholate (DHC) was infused into male rats at a rate of 80 mumoles per hour over an 18-hour period. Bile was collected by fistula and phospholipid and cholesterol content was measured in bile, liver homogenates, and isolated liver plasma membranes (LPM) enriched in bile canaliculi. Na+, K+-ATPase, Mg2+-ATPase, 5'-nucleotidase, and alkaline phosphatase activities were also measured in LPM. NaTc infusions enhanced cholesterol and phospholipid output in the bile in association with a significant increase in phospholipid in both LPM and liver homogenate. Although DHC infusions resulted in a comparable excretion of bile acid, phospholipid and cholesterol output in bile did not increase from control values and the concentration of these lipids in LPM and liver homogenate also did not change. However, LPM Na+, K+-ATPase significantly increased after DHC infusions compared to NaTc-infused animals or controls. Neither bile acid altered the activities of Mg2+-ATPase, 5'-nucleotidase, or alkaline phosphatase. Both bile acids increased the diameter of the lumen of the bile canaliculus as assessed by scanning electron microscopy and produced irregularities and outpouchings in the canalicular membrane. Diverticuli and loss of microvilli were most prominent with DHC infusions whereas canalicular side branching and the density of microvilli, either remained unchanged or increased following NaTc infusions. Although the morphologic findings are qualitative, the results of these studies indicate that chronic choleretic infusions of NaTc and DHC have divergent effects, not only on enzyme activities in liver plasma membrane, but on phospholipid composition and 3-dimensional structure. These findings suggest that bile acids may after biliary secretion not only through their osmotic effects, but by modifying lipids and enzymes in the membrane of the bile canaliculus.
...
PMID:Effects of chronic choleretic infusions of bile acids on the membrane of the bile canaliculus. A biochemical and morphologic study. 13 67

The activities of 5'-nucleotidase, K+, Na+-activated Mg2+-dependent adenosine triphosphatase (ATPase) and leucine-beta-naphthylamidase were determined from 17 rheumatoid synovial fluids and from extracts of the corresponding synovial tissues. There was little correlation between the enzyme activities in the synovial fluids and those in the respective synovial-tissue extracts. In seropositive cases of rheumatoid arthritis the activities of 5'-nucleotidase and leucine-beta-naphthylamidase in the synovial-tissue extract were higher than in seronegative cases. Also, the ratios of the enzyme activities in the synovial fluids to the resepctive activities in synovial tissue were lower in the seropositive cases. The activity of 5'-nucleotidase in the synovial tissue decreased during gold treatment.
...
PMID:The activities of plasma-membrane marker enzymes in rheumatoid synovial tissues and fluids. 13 78

A rabbit antiserum to first-trimester human fetal tissue had greater reactivity in complement fixation and saturation binding assays with fetal tissues than with both a pool of normal adult lung, liver, and kidney and pools of the individual organs. This anti-fetal membrane reactivity was only partially inhibited by carcinoembryonic antigen. The serum still reacted strongly with human fetal and tumor cells after rendering it specific for plasma membrane components by adsorption to and elution from intact human fetal tissue culture cells. This plasma membrane-specific serum was then used to monitor the purification of the fetal membrane-associated antigens. The fetal antigens copurified with the putative plasma membrane enzymatic markers 5'-nucleotidase and Mg2+-adenosinetriphosphatase through differential and density gradient centrifugation. Insulin-binding activity only partially copurified with the antigenic activity. Little antigenic activity was found in nuclear and mitochondrial fractions. The isolation protocol gives fetal plasma membrane-associated antigens in approximately 50% yield with moderate purification. The sera and isolation procedures described should have general utility for the detection of human oncofetal antigens.
...
PMID:Isolation and partial characterization of plasma membranes bearing human fetal-associated antigens. 14 4

1. Homogenates of guinea-pig left ventricle were fractionated by differential pelleting and by centrifugation on continuous sucrose density gradients. 2. The principal subcellular organelles of myocardium, characterized by their marker enzyme content, were resolved by density gradient centrifugation in a small-volume zonal rotor. The equilibrium densities (p) of the principal organelles are (with marker enzymes in parentheses): sarcolemma, 1-12 (5'-nucleotidase); lysosomes, 1-16 (N-acetyl-beta-glucosaminidase); mitochondria, 1-17 (cytochrome oxidase); peroxisomes, 1-18 (catalase); cytosol (lactate dehydrogenase). 3. The subcellular distribution of various adenosine triphosphatase activities and previously unassigned enzymes was determined. Leucyl-beta-naphthylamidase and gamma-glutamyl transpeptidase showed both cytosol and sarcolemma components. Ca2+-dependent adenosine triphosphatase showed dual localization to the mitochondria and to the sarcolemma.
...
PMID:Analytical subcellular fractionation of guinea-pig myocardium. 14 54

The 5'-nucleotidase properties of isolated lymphocyte plasma membranes from young pig mesenteric nodes are described; nucleosides-5'-monophosphates are the substrates of this specific enzyme. Concanavalin A inhibits this enzyme; on the same membranes this mitogen does not affect alkaline phosphatase and activates the membrane bound (Ca2+) ATPase. The 5'-nucleotidase inhibition is due to a specific interaction of Con A with carbohydrate groups of the membrane; its high positive cooperativity suggests that the lectin promotes reorganization of the membrane bound 5'-nucleotidase. Solubilization of the 5'-nucleotidase does not prevent the effect of Con A and the solubilized enzyme is firmly bound by Con A-Sepharose 4B; these results suggest that Con A inhibits the enzyme by a direct interaction and that 5'-nucleotidase can be considered as an eventual receptor for the lectin.
...
PMID:[5'-Nucleotidase activity of lymphocyte plasma membranes. Effect of concanavalin A]. 14 52

A procedure for the isolation of plasma-membrane-enriched fractions from bovine 'pars intermedia' and neurohypophysis is described. Various fractions are isolated by differential centrifugation and discontinuous sucrose density gradients. The plasma-membrane-enriched fractions have a density in sucrose of 1.14 and 1.16 and the yields are 1.8 mg and 1.5 mg per gram of tissue for the pars intermedia and neural lobe, respectively. The fractions are characterized by electron microscopy and enzymatic assays. The plasma membrane fractions are mainly vesicular in nature and are free of nuclei, mitochondria, and microsomes when examined by electron microscopy. 5'-Nucleotidase (EC 3.1.3.5) and Mg2+-(Na+ + K+)-ATPase (EC 3.6.1.3) activities are concentrated in the plasma-membrane-enriched fraction. Also, adenylate cyclase (EC 4.61.1) shows a 5 to 10-fold purification in the isolated membrane fraction. NaF (10mM) gives a two to three-fold stimulation of enzymatic activity in all fractions studied The yields of adenylate cyclase, 5'-nucleotidase, and Mg2+-(Na+ +K+)-ATPase are about 6% in the membrane fraction.
...
PMID:Purification of plasma membrane fractions from the bovine pars intermedia and neurohypophyseal lobe and properties of associated adenylate cyclase. 14 70

1. Treatment of hamster heart cells in primary culture with 5-bromo-2'-deoxyuridine resulted in the greatly increased activity of a particulate Ca2+- or Mg2+-dependent ATPase (adenosine triphosphatase). 2. 5-Bromo-2'-deoxyuridine exerted these effects only when it was incorporated into cellular DNA, and then in a concentration-dependent manner. 3. Serially replated cells contained less of the activity (expressed as a function of total cell protein) than did the primary cultures, but the stimulation caused by 5-bromo-2'-deoxyuridine addition was much greater. 4. The affected enzyme was apparently localized in the plasma membrane of the cells with its active centre exposed to the outer environment [ecto-(ATPase) dependent on Ca2+ or Mg2+].5. The activity was unaffected by treatment with p-chloromercuriphenylsulphonate, ouabain andverapamil. 6. Ecto (5'-nucleotidase) activity was not increased by 5-bromo-2'-deoxyuridine treatment of cells, and ecto-(p-nitrophenyl phosphatase) activity was only slightly enhanced.
...
PMID:5-bromo-2'-deoxyuridine-stimulated calcium ion- or magnesium ion-dependent ecto-(adenosine triphosphatase) activity of cultured hamster cardiac cells. 14 81

Albion mice were immunized with a suspension of sheep erythrocytes. The animals were killed on the fifth and eighth day, and lymphocytes were taken from their spleen tissue. Studied was the activity of the adenosinetriphosphatase and 5'-nucleotidase in the lymphocytes during the immunogenesis in terms of their link with the cellblast transformation. The enzyme activity was determined by the method of Emmelot, Bos, and the extent of the blast transformation was expressed by the so-called blastogenic index (BI). It was found that: 1. During immunogenesis 32% of the lymphocytes in the mouse spleen are transformed into blast cells. 2. The activity of 5'-nucleotidase drops, and that of adenosinetriphosphatase rises. 3. Parallelism exists between the extent of the lymphocyte blast transformation and the level of adenosinetriphosphatase. 4. The drop in the activity of 5'-nucleotidase is considered to be the aftermath of the drop in the intracellular adenosinetriphosphatase content.
...
PMID:[Adenosine triphosphatase and 5'-nucleotidase activity of antigen-stimulated lymphocytes]. 14 9

Cholestatic jaundice is one complication of nonhepatic gram-negative bacterial infection. The endotoxin of Escherichia coli has been reported to cause cholestasis by inhibiting the bile salt-independent fraction (BSIF) of bile in the perfused rat liver. Accordingly, the effects of lipopolysaccharides (LPS) of E. coli and Salmonella enteritidis on the Na+, K+-adenosinetriphosphatase (ATPase) in canalicular-enriched plasma membranes of rate liver were examined. At 20 microgram/ml, both endotoxins inhibited this enzyme by approximately 40%. Maximal inhibition (70%-80%) occurred at concentrations of greater than or equal to 120 microgram/ml. The LPS of neither organism exerted any effect on the activity of Mg++-ATPase or 5'-nucleotidase in the same preparations. Inhibition by the E. coli LPS appeared to be noncompetitive in nature, and the calculated Ki was 45 microgram/ml. Since the Na+, K+-ATPase may be responsible for the elaboration of BSIF, inhibition of this enzyme could be the underlying mechanism for the endotoxin-induced cholestasis.
...
PMID:Inhibition of Na+, K+-adenosinetriphosphatase by endotoxin: a possible mechanism for endotoxin-induced cholestasis. 14 99


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

---