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)

1. Freshly prepared microsomal fractions of the outermost cortex of guinea pig kidney show an Mg-2+-dependent ATPase activity which is partially inhibited by 100 mM NaCl, LiCl, KCl, RbCl, CsCl, NH4Cl or choline chloride. 2. If the microsomal preparation is aged by storage at 4 degrees C for 10-15 days, the Mg-2+-dependent activity shows stimulation by Na-+ and Li-+ but not by K-+, Rb-+, Cs-+, NH4-+ or choline. 3. Stimulation is similar with sodium salts of Cl-minus, HCO3-minus, CH3COO-minus, BR-minus, SO4-2-minus or methylsulphonate. 4. Stimulation is insensitive to 1 mM and 10 mM ouabain. 5. Stimulation is unaltered by the presence of 0.5 mM ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-tetracetic acid. 6. Stimulation is 100% inhibited by 2 mM ethacrynic acid, a concentration which inhibits only 30% of the Mg-2+-dependent ATPase and 50% of the (Na-++K-+)-stimulated ATPase. 7. Some of these characteristics coincide with those of an ouabain-resistant, K-+-independent, ethacrynic acid-sensitive mode of Na-+ extrusion out of guinea pig kidney cortex cells.
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PMID:Ouabain-insensitive Na+ stimulation of an Mg-2+ -dependent ATPase in kidney tissue. 12

Investigations have been made of the kinetic effects of the antibiotic aurovertin on the ATPase and ITPase activity of isolated rat liver mitochondrial ATPase. Unusual patterns of inhibition, decreasing slope, and increasing y-intercept values of double reciprocal plots, were observed with Mg-ATP as the substrate under various conditions. Under specified conditions, aurovertin stimulated hydrolysis of MgATP. The inhibition of MgITP hydrolysis was uncompetitive. Aurovertin eliminated the HCO3-minus stimulation of MgATP hydrolysis. The implications of these findings for the mechanism of mitochondrial ATPase are briefly discussed.
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PMID:Influence of aurovertin on mitochondrial ATPase activity. 12 77

HCO3--sensitive ATPase was found in nuclear and plasma membrane fractions of Ehrlich ascites tumour cells and lymphoma NK cells. HCO3--ATPase was not sensitive to monovalent cations and to ouabain (10(-4) M). The 60 mM HCO3- is the concentration of maximal activation of the HCO3--sensitive ATPase. The HCO3--sensitive ATPase was inhibited by anions in the sequence: SCN- greater than F- greater than ClO4- greater J-. The anions Br-, NO3-, HSO3- were not effective.
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PMID:[HCO3-sensitive adenosinetriphosphatase from ascites tumour cells]. 12 89

Light fractions of homogenates of rat heart, diaphragm, lung, liver, kidney, spleen, muscle, brain, gastric mucosa and of red blood cell membranes contained HCO3-stimulated ATPase. ATPase activity was increased by 15-77% by adding 25 mM HCO-3.
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PMID:[HCO3-stimulated ATPase from rat tissue homogenates]. 12 70

A bicarbonate-stimulating effect on the ATPase activity in membranes of rat erythrocytes depended upon pH, concentration of Mg2+ and HCO3-ions. Sodium azide and sodium thiocyanate distinctly inhibited the ATPase activity; pentachlorphenol and 2,4-dinitrophenol did not change it. Properties of the bicarbonate-stimulated ATPase from erythrocyte membranes were shown to be similar to the properties of the HCO3--ATPases from other cells.
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PMID:[Bicarbonate-stimulated ATP-ase from membranes of rat erythrocytes]. 12 56

Activity of ATPases was studied in erythrocytes of patients with phobia neurosis of the 11 degree and in erythrocytes of mentally healthy patients. The total Mg2+, Na+, K+-dependent ATPase activity of patients with the neurosis was unaltered in blood. But the Mg2+-ATPase activity was increased and the Na+, K+-ATPase activity was decreased in the patients as compared with the control group. Addition of lithium carbonate into incubation mixtures exhibited different effect on the Na+, K+-stimulated ATPase depending upon the initial activity of the enzyme. In blood of patients with low initial values of the enzymatic activity it was increased. But the Na+, K+-ATPase activity was decreased by lithium carbonate in those cases when the initial enzymatic activity was high. Quantitatively the effect of lithium on the enzymatic activity was similar in the both groups of neurotic patients studied (although the direction of changes was oposite).
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PMID:[Activity of Mg 2+, Na+ and K+ stimulated ATPase in erythrocytes of patients with phobic neurosis and the effect of lithium carbonate on the enzymatic activity]. 12 54

The rat salivary duct epithelium, which actively transports Na+, K+, and H+/HCO3- in a manner similar to renal distal tubules, was used as a model tissue to study the mechanism of action of triamterene on electrolyte transport. 10(-4) M triamterene completely blocked Na+ resorption and lowered net K+ secretion to half that of controls, whereas HCO3- accumlated in the lumen, probably due to a decrease in H+ secretion. The rates of K+ and H+/HCO3- transport in the presence of triamterene did not differ from those determined after omission of Na+ from the luminal fluid. This was considered to be evidence against a direct action of triamterene on transport of K+ and H+/HCO3-. Triamterene rapidly and reversibly reduced the transepithelial electrical potential difference. This was due to almost complete abolition of Na+ conductance of the luminal membrane at 10(-4) M triamterene, whereas K+ conductance was not altered. Triamterene, administered in vitro from the interstitial side of the isolated duct epithelium was ineffective even at the highest concentrations. The activities of the Na-K-ATPase, the Mg-ATPase and the microsomal HCO3-ATPase were influenced by 10(-4) M triameterene in a similiar fashion. These effects were clearly demonstrated only in the homogenate of the duct tissue and not in intact cells in the isolated duct preparation. Therefore they were considered unspecific. The transport studied demonstrate a primary effect of triamterene on Na+ entry from lumen to cell. Influences on net K+ and H+/HCO3 transport are secondary consequences of functional coupling between movement of Na+ and movement of K+ and H+ across the luminal cell membrane.
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PMID:On the mechanism of action of triamterene: effects on transport of Na+, K+, and H+/HCO3- -ions. 13 Feb 43

In the presence of high concentrations of K+, additions of HCO3- as low as 0.35 mM caused a 23% increase in swelling, and concomitant increases in the chloride content of incubating monkey cerebrocortical slices. The uptake of chloride was accompanied by increased uptake of sodium and was highly temperature dependent, showing a marked activation at approximately 30 degrees C. A similar temperature activation was also found for a Mg2+-dependent, HCO3-stimulated ATPase activity in monkey cerebral cortex, consistent with a possible role for this enzyme in the K+ and HCO3-dependent swelling process and its associated ion movements. K+-dependent, HCO3-stimulated cerebrocortical tissue swelling with uptake of Na+ and Cl- was inhibited by acetazolamide indicating that carbonic anhydrase was also involved. The addition of ouabain also inhibited swelling and K+ and Cl- uptake at low concentrations, but led to increased swelling at higher concentrations ( greater than 10 mum). A similar biphasic effect on swelling was also seen following addition of ethacrynic acid.
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PMID:The effects of temperature and inhibitors on HCO3-stimulated swelling and ion uptake of monkey cerebral cortex. 13 Sep 62

The salivary duct epithelium, which actively transports Na+, K+ and H+/HCO3/- similarly to renal distal tubules, was used as a model tissue to study the mechanism of action of triamterene (Jatropus, Dyrenium) on electrolyte transport. Triamterene was only effective when administered from the luminal side of the duct, not from the interstitial side. 10-4 M triamterene completely blocked Na+-reabsorption. At the same time K+ secretion dropped to half of control, whereas HCO-/3 accumulated in the duct lumen following reduced H+ secretion. These changes in electrolyte transport are caused by an inhibition of Na+-entry by triamterene as suggested by measurements of ion permeability of the cell membrane. Triamterene has no specific effect on the membrane-bound ATPase. Since Na+-entry is functionally coupled with exit of K+ and H+ from cell to lumen, impairment of Na+-entry by triamterene necessarily causes reduction of K+ and H+ secretion into lumen.
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PMID:[Inhibition of the exchange of Na+ for K+ and and H+ by triamterene (in epithelia)(author's transl)]. 13 88

Dog pancreatic tissue, incubated in a modified Wachstein-Meisel medium, showed two different adenosine triphosphatase activities. One of them is located at the apical border of the cells lining the intralobular ducts and of the centroacinar cells and is stimulated by HCO3-, depressed by SCN- and OCN- and completely abolished by CN-. The other is located at the intracellular clefts of the epithelium lining the interlobular ducts and is stimulated by Mg++. These findings correlate well with the results of incubation of homogenates of fresh and fixed tissues. Their significance with respect to the role of different segments of the duct system in the formation of the pancreatic juice is discussed.
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PMID:Cytochemical study of the distribution of adenosine triphosphatase in the pancreas of the dog. 13 6


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