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)

An investigation of isolated and purified heart sarcoplasmic reticulum performed in the current study indicates the presence of significant creatine phosphokinase (CPK) activity in this preparation. The localization of CPK on the membrane of sarcoplasmic reticulum has been revealed also by an electron microscopic histochemical method. Under the conditions of the Ca(2+)-ATPase reaction in the presence of creatine phosphate, the release of creatine into the reaction medium is observed, the rate of the latter process being dependent on the MgATP concentration in accordance with the kinetic parameters of the Ca2+-ATPase reaction. CPK localized on the reticular membrane is able to maintain the high rate of calcium consumption by the sarcoplasmic reticulum vesicles. The results obtained demonstrate the close functional coupling between CPK and Ca2+-ATPase in the membrane of sarcoplasmic reticulum and indicate the important functional role of CPK in supplying energy for the Ca(2+)-ATPase reaction and ion transport across the membrane of heart sarcoplasmic reticulum.
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PMID:The role of creatine phosphokinase in supplying energy for the calcium pump system of heart sarcoplasmic reticulum. 4 83

Rabbit antiserum was prepared against a partially purified Ca2+, Mg2+-dependent ATPase [EC 3.6.1.3] of the SR isolated from chicken skeletal muscle. The gamma-globulin fraction of antiserum contained antibodies which combined with the purified ATPase and the SR vesicles. Binding of the antibodies strongly inhibited active transport of Ca2+ ions into the SR, but not passive leakage of Ca2+ ions from the SR. The antibodies scarcely affected the ATPase activity.
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PMID:Inhibition of Ca2+ uptake into fragmented sarcoplasmic reticulum by antibodies against purified Ca2+, Mg2+-dependent ATPase. 5 12

Cardiac tissue obtained by left-ventricular endomyocardial biopsy from patients with valvular heart-disease was assayed for marker enzyme activities of subcellular organelles and these were correlated with left ventricular function as assessed by haemodynamic studies. In patients with poor left ventricular function, calcium-dependent adenosine-triphosphatase (A.T.P.ase) activity, predominantly localised to the myofibrils, was strikingly reduced. Activity of lactate dehydrongenase, a cytosol enzyme, was significantly increased in tissue from patients with poor left ventricular function. The activity of enzymes associated with sarcolemma (5'-nucleotidase), mitochondria (glutamate dehydrogenase and monoamine oxidase), microsomes (neutral alpha-glucosidase), and lysosomes (acid phosphatase, N-acetyl-beta-glucosaminidase) was no different in patients with good or poor left ventricular function. It is suggested that reduced myofibrillary A.T.P.ase concentration is the biochemical basis for the impaired ventricular function.
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PMID:Enzymic analysis of cardiac biopsy material from patients with valvular heart-disease. 5 85

The distribution, histochemical properties and ultrastructural localization of adenosine triphosphate (ATP) hydrolyzing enzymes in the tanycyte ependyma of the third ventricle have been studied in female Wistar rats. Using a calcium-cobalt procedure and a lead capture technique, splitting of ATP could be demonstrated in perikarya and processes of tanycytes in the region of the ventromedial nucleus. The reaction showed no dependence on magnesium or sodium ions, did not occur with other monodi-, and tri-phosphates as substrates, and was inhibited by p-chlormercuribenzoate (PCMB) and sodium fluoride, but not by ouabain. With the calcium-cobalt method the highest intensity of reaction was found at pH 9.4, whereas the lead method gave optimal results at pH 6--8. At the ultrastructural level, the reaction product was found at the outer surface of the plasma membranes of tanycytes and reached its highest concentrations in the region of the region of the apical microvilli; From the findings it is concluded that splitting of ATP in tanycytes is due to a true ATPase. The enzyme might be involved in an active transport of substances by tanycytes.
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PMID:Distribution and properties of an adenosine triphosphatase in the tanycyte ependyma of the IIIrd ventricle of the rat. 6 Mar 13

The effect of the transport ATPase inhibitor, quercetin on histamine secretion from antigen sensitized mast cells was examined. At micromolar concentrations, quercetin had an immediate inhibitory effect on histamine secretion mediated by antigen, concanavalin A and ATP but it had little effect on release induced by the ionophores A23187 and X537A. Quercetin exerts its effect after the binding of the releasing ligands and the distinction between its effect on ligand induced and A23187 induced secretion suggests that it affects the normal path of Ca2+ entry into the cell. The inhibitory effects of quercetin were compared with those of the structurally related anti-allergic drugs cromoglycate and AH7725.
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PMID:Quercetin: a novel inhibitor of Ca2+ influx and exocytosis in rat peritoneal mast cells. 7 Feb 22

A selective staining of the nucleus of both the cells in an islet (of Langerhans) and the acinar cells could be observed after treatment with bromide-water in an ATPase-medium (calcium-cobalt-method) on a cryostatsection of rat pancreas. Furthermore the behaviour of the other metal ion forming a complex has been tested in place of cobalt salt. As conditioned for the staining reaction the hydrolysis of nucleic acid with oxidation of its base by bromide-water and also the complex formation of Co++ with compounds similar to alloxan, resulted from oxidation were discussed.
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PMID:[The reactive behaviour of the cell nucleus after a pretreatment with a bromide solution and the application of the calcium-cobalt-method for the ATPase evidence (author's transl)]. 7 39

Ethacrynic acid, a known inhibitor of both Na+--K+ and Mg2+-activated ATPases, effectively inhibits histamine release from antigen-challenged human basophils in vitro. Ouabain, an inhibitor specific for Na+--K+-activated ATPases, shows no effect upon the quantity of histamine released from the antigen-challenged basophils. Ethacrynic acid also effectively inhibits Ca2+--ionophore A23187-induced release, implying it inhibits the Ca2+-dependent secretory stage of the histamine-release process. Inhibition of ATPases and histamine release by ethacrynic acid both require the presence of the olefinic bond in the ethacrynic-acid molecule. Possible utilization of analogues of ethacrynic acid as anti-allergic drugs and as a device to investigate the ATPase system of histamine-releasing cells is suggested.
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PMID:Blocking of histamine release from human basophils in vitro by the ATPase inhibitor, ethacrynic acid. 7 37

A crude plasma membrane fraction from the homogenate of purified rat mast cells demonstrates a high degree of Ca2+-dependent and Mg2+-dependent adenosine triphosphatase (ATPase) activity. The microsomal and mitochondrial fractions show negligible amounts of the Ca2+ and Mg2+-activated ATPases. The broad ATPase inhibitor, ethacrynic acid, effectively blocks the mast cell ATPase activity while ouabain demonstrates little inhibitory effect. Correspondingly, ethacrynic acid inhibits histamine release from antigen-challenged mast cells while ouabain does not. Both ATPase inhibition and histamine release inhibition by ethacrynic acid require the presence of the olefinic bond in the ethacrynic acid molecule.
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PMID:Ethacrynic acid inhibitable Ca2+ and Mg2+-activated membrane adenosine triphosphatase in rat mast cells. 7 76

Sodium glycocholate was shown to remove a Ca2+-activated adenosine triphosphatase from the external surface of the rat mast cell without causing lysis. Sensitized mast cells pretreated with sodium glycocholate showed a decrease in histamine-releasing capacity when triggered with antigen, Synacthen and ATP. Release induced by calcium ionophore A23187 was unaffected.
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PMID:Effect of removal of calcium-activated adenosine triphosphatase from rat mast cells by treatment with sodium glycocholate. 7 27

The K+-stimulated, ouabain-insensitive ATPase activity present in vesicles of microsomal fractions from hog gastric mucosa can be demonstrated in fresh preparations by adding Ca2+ (micron range) to the incubation medium. Ca2+ effect is similar but not additive to the effect of gramicidin or freezing. High Ca2+ concentrations (1 mM) produce an inhibitory effect on the K+-stimulated ATPase activity. This effect is not seen in the presence of gramicidin. Calcium increases the magnitude of ATP-driven H+ uptake in vesicles exposed to K+ for periods of time up to 60 min. At longer times of exposure (120 min) the response does not differ from controls. It is concluded that Ca2+ at low concentrations (micron range) enhances the K+ permeability of the vesicular membrane. At higher concentrations (mM range), Ca2+ becomes inhibitory to the K+ permeability. A role for Ca2+ as a second messenger in stimulus-secretion coupling in the parietal cell is discussed.
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PMID:Effect of calcium on the H+/K+ ATPase of hog gastric microsomes. 8 6


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