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)

Dependence of the HCO--3-stimulated ATPase activity from nuclei and mitochondria of rat ovary ascites tumor cells on pH and concentration of bicarbonate ions was studied. PCMB, NaN3, NaCNS, NaClO4 and NaF inhibited the HCO--3-stimulated ATPase activity. The properties of HCO--3-sensitive ATPase from rat ovary ascites tumor cells were similar to that of HCO--3-ATPases from other tissues.
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PMID:[HCO3-stimulated adenosine triphosphatase in rat ovarian tumor cells]. 2 52

Rabbit cardiac myosin, isolated from frozen tissue, was effectively purified by batchwise treatment with DEAE-cellulose in addition to suing cilution-precipitation techniques. An extensive experimental program was subsequently carried out with respect to the enzymic amino acid, optical and physicochemical properties of native cardiac myosin. This program has included the following: examination of the effects of pH and varying concentrations of ATP, CaCl2, MgCl2, and PCMB on its ATPase activity; measurement of its circular dichroic spectrum in solvent buffers, at different pH or containing ATP in the absence or presence of Ca-2+ or Mg-2+ ions; study of the concentration dependence of its viscosity and sedimentation velocity at low temperatures; and investigation of its molecular weight by the Archibald method and low- and high-speed sedimentation equilibrium. The results of these studies were consistent with the interpretation that cardiac myosin is comprised of highly asymmetric, semi-rigid molecules with a molecular weight in the order of 4.7 times 10-5, which display non-ideality even in solvent buffers of high ionic strength at neurtal pH. In addition, computer analysis of the high-speed sedimentation equilibrium data has provided evidence for the presence of a self-association reaction at low protein concentration. Even though the specif ATPase activity of cardiac myosin was found to be approximately one-third that reported for skeletal myosin in all cases, it was concluded, on the the basis of the essentially analogous physical and chemical properties of rabbit cardiac and skeletal myosin, that the two proteins are very similar in terms of molecular size, shape, and secondary structure.
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PMID:Rabbit cardiac myosin. I. Physical and chemical characterization of the native molecule. 12 22

A method is presented for obtaining the preparation of N+, K+-ATPase from the cattle brain. The specific activity of the preparation is 5 units (mu mole Pi per 1 min) per 1 mg of protein. A water-soluble derivate of carbodiimide is shown to inhibit reversibly both Na+, K+-ATPase and K+-phosphatase. ATP, Na+ and K+ manifest a protective effect against inhibition, and Na+ and K+ revealed a competition with the inhibitor for the enzyme. p-Chloromercuribenzoate inhibits irreversibly Na+, K+-ATPase and K+-phosphatase activities. The substrates ATP and p-nitrophenylphosphate protected these activities against inhibition. The phosphororganic compound O-n-butyl-S-(beta-ethyl-mercaptoethyl)-methyl thiophosphate has no significant effect on the Na+, K+-ATPase and K+-phosphatase activities.
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PMID:[Isolation of active preparation of Na+, K+-ATPase from cattle brain and study of the role of carboxyl, sulfhydryl and hydroxyl groups]. 12 66

The enzymatic properties of plasma membrane-bound Na+, K+-ATPase [EC 3.6.1.3], isolated with high specific activity and in good yield from pig thyroid cells, were examined. The enzyme activity required the presence of both Na+ and K+ at physiological concentrations; it exhibited high sensitivity to K+ and an absolute requirement for Na+. It showed highly specific requirement for Mg2+ and ATP. The apparent Km for ATP was 0.14 mM under the assay conditions. Arrhenius plots had a point of inflection at about 22 degrees C, activation energies being 24.2 kcal/mol at 5-22 degrees C and 19.0 kcal/mol at 22-40 degrees C. In addition to ouabain, the ATPase was strongly inhibited by fluoride and the SH-blocking reagent, PCMB. Iodide and TSH had no appreciable effect on the enzyme activity.
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PMID:Properties of the Na+, K+-stimulated adenosine triphosphatase system associated with the plasma membrane of pig thyroid glands. 14 Aug 65

Shifts in the distribution of the monovalent cations Na+ and K+ between the extra- and intracellular space seem to be important for the secretory response of the beta-cell. An attempt was therefore made to study the enzyme responsible for monovalent cation transport, the (NaK)-activated ATPase. In the presence of NaN3 as inhibitor of the mitochondrial Mg-ATPase, a NaK-ATPase with a specific activity of 72 mU X mg protein-1 could be demonstrated in crude membrane preparations of rat pancreatic islets. The enzyme, which was inactive in the absence of Mg++, needed both Na+ and K+ for activation and was inhibited by ouabain and PCMB. The main part of the NaK-ATPase was localized in the microsomal fraction. Glucose, sulphonylureas, somatostatin and diazoxide were without effect on NaK-ATPase.
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PMID:NaK-ATPase in rat pancreatic islets. 14 87

The central nervous systems of web-building spiders (Araneidae, Agelenidae) and hunting spiders (Lycosidae, Salticidae) were tested for non-specific and specific phosphatases. Acid phosphatase exhibited weakly to moderately positive reactions in the neuronal cell bodies and in the neuropile fibre mass of all species investigated. Alkaline phosphatase could only be demonstrated in the external and internal neural lamellae of the brain and ventral cord of several specimens of the araneid species investigated. Tests for thiamine pyrophosphatase were negative with both the lead and calcium-cobalt methods. Distinctive positive reactions for adenosine triphosphatase were visible in the nervous system of all the species used, being especially strong in the optic ganglia of the hunting spiders. The demonstration of adenosine triphosphatase was only possible when applying the calcium-cobalt method after Padykula and Herman, while the lead method after Wachstein and Meisel did not produce any staining reaction at all. Controls of the histochemical reaction showed that the enzyme was activated by Ca2+ and inhibited by sulphydryl destroying reagents (e.g. PCMB), but was insensitive to ouabain. It could be probably classified as a mitochondrial proton-translocating adenosine triphosphatase.
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PMID:Phosphatases in the central nervous system of spiders (Arachnida, Araneae). 21 10

A well-characterized chicken osteoclast plasma membrane vesicle preparation manifested Mg2(+)-dependent ATP hydrolyzing activity of 0.213 mumol inorganic phosphate released per mg protein per minute (n = 7). The Mg2+ dependence showed a high-affinity component with a KMg of 1.293 microM and Vmax of 0.063 mumol Pi per mg protein per minute, and a low-affinity component with a KMg of 297.6 microM and a Vmax of 0.232 mumol Pi per mg protein per minute. The Mg2(+)-ATPase activity was inhibited by N,N'-dicyclohexylcarbodiimide (DCCD, 0.2 mM, 50.7%), N-ethylmaleimide (0.5 mM, 34.6%), nolinium bromide (1 mM, 29.9%), 4,4'-diisothiocyano-2,2'-stilbene sulfonic acid (DIDS, 1 mM, 45.1%), and p-chloromercuribenzoic acid (PCMB, 0.1 mM, 33.8%). Sodium orthovanadate (Na3 VO4) at 1 microM had no effect but caused 29.5% inhibition at 1 mM. Na+ could substitute for K+ without loss of activity, NO3- caused 19.5% inhibition when substituted for Cl-, and acetate replacement of Cl- resulted in 36.4% stimulation of Mg2(+)-ATPase. ATP, GTP, ITP, CTP, and ADP were all hydrolyzed effectively. DCCD (0.2 mM), NEM (0.5 mM), nolinium bromide (1 mM), and DIDS (50 microM) almost completely abolished proton transport as measured spectrofluorometrically by acridine orange quenching. Na3 VO4 (1 mM) had no effect, and duramycin (80 micrograms/ml) inhibited transport 52.7%. K+ replacement of Na+ caused a 79.2% increase in initial proton transport rate. NO3- and acetate substitution of Cl- resulted in a 46.1 and 55.7% decrease in transport, respectively. ATP supports transport far more effectively than the other nucleotides tested. ADP was ineffective. Experiments using the potassium ionophore, valinomycin, indicated that the proton pump functions electrogenically, with Cl- most likely cotransported by an anion transporter. The proton pump also seems to have at least one anion-sensitive site, elucidated by experiments in the presence of NO3- and Cl-.
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PMID:Biochemical characterization of an electrogenic vacuolar proton pump in purified chicken osteoclast plasma membrane vesicles. 216 21

The effects of four organic mercury compounds (methylmercuric chloride; bromomercurihydroypropane, BMHP; chlormerodrin; p-chloromercuribenzoic acid, PCMB) on mechanical and electrical functions of guinea-pig papillary muscles were investigated. An initial decline in contraction force was followed by a transient positive inotropic response. The first was accompanied by a shortening of the action-potential duration and by a reduction of the depolarization velocity and the duration of the Ca2+-dependent slow response. The latter was characterized by an indirect component (release of noradrenaline) and by a direct component, which was dependent on the stimulation rate and on the extracellular concentration of Na+ and K+. The direct positive effect, therefore, was likely to have resulted from inhibition of the sarcolemmal Na+ + K+-ATPase. This notion was confirmed by experiments with isolated membrane particles. The prevalence of the negative or positive inotropic action of these compounds could be ascribed to their lipophilic or hydrophilic properties, respectively.
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PMID:The action of organic mercury compounds on the function of isolated mammalian heart muscle. 253 72

The bulk of NADH kinase of Saccharomyces cerevisiae was recovered in the mitochondrial fraction prepared from spheroplasts. Most of the NADH kinase was localized in the inner membrane fraction, which was separated from other mitochondrial components by the combined swelling, shrinking, and sonication procedure. Treatment of mitoplasts with antiserum against the NADH kinase caused inactivation of the enzyme. On the contrary, no influence was observed upon the same treatment of intact mitochondria. p-Chloromercuribenzoate and eosin-5-maleimide inactivated the enzyme without affecting the matrix ATPase. The NADH kinase was enzymatically iodinated in mitoplasts, but not in the intact mitochondria. These results support the conclusion that NADH kinase is localized and functions at the intermembrane space side of the mitochondrial inner membrane. It is evident that the NADH kinase is encoded by nuclear gene(s) because it is synthesized in the presence of chloramphenicol or acriflavine, and a significant amount of the enzyme was detected in mitochondrial DNA-deficient mutants.
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PMID:Localization of the NADH kinase in the inner membrane of yeast mitochondria. 254 21

The properties of ATPase activity were examined in the intact cells of yeast. The activity was stimulated by Mg2+, Mn2+ and Co2+. The activity was inhibited by NaN3 and by high concentrations of NaF, NaVO3 and PCMB. Optimal pH for the activity was approximately 8. The maximum value of the activity was obtained in the cells at the early stationary phase and it decreased in 3 hr after transfer to sporulation medium.
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PMID:Properties of ATPase activity in intact vegetative cells and sporulating cells of yeast Saccharomyces cerevisiae. 293 54


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