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)

HgC12-induced renal tubular lesions in the rat present histochemically with a transitory decrease of alkaline phosphatase, adenosinetriphosphatase (ATPase), and leucine-aminopeptidase activity. The toxic alterations of enzyme activity were more pronounced in the pars recta of the proximal tubule and in the loop of Henle, as compared with the tubulus contortus I. L-thyroxine treatment leads to an accelerated reversal of that enzymatic defect, followinga characteristic pattern, and to a differentiating increase of acid phosphatase and ATPase activity in certain parts of the normal renal tubule. The observations are discussed with reference to the specific mode of action of sublimate and l-thyroxine upon the tubular enzymes and to the well-known metabolic and functional influences of thyroid hormone on the kidney.
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PMID:Influence of L-thyroxine upon enzymatic activity in the renal tubular epithelium of the rat under normal conditions and in mercury-induced lesions. I. Histochemical studies of alkaline phosphatase, acid phosphatase, adenosine- tri-phosphatase and leucine-aminopeptidase. 19 Jul 63

Rough microsomes were subfractionated on the basis of different properties in order to investigate the nature and extent of the enzyme heterogeneity of these vesicles. A discontinuous gradient, containing monovalent cations allowed the separation of a ribosome-poor membrane fraction which was enriched in electron transport enzymes and relatively poor in phosphatases. Zonal centrifugation on a stabilizing gradient separated 3 fractions characterized by enrichment of electron transport enzymes, glucose-6-phosphatase and adenosinetriphosphatase, respectively. An essentially similar pattern was seen when ribosomes were removed with EDTA and the denuded vesicles subfractionated on a sucrose gradient. Rough microsomes from phenobarbital-treated rats exhibited the same pattern both qualitatively and quantitatively. It appears that electron transport enzymes and two types of phosphatases are heterogeneously distributed among rough microsomal vesicles.
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PMID:Lateral enzyme topology in the rough endoplasmic reticulum of rat liver. 19 72

Inorganic lead ion, in micromolar concentrations, reversibly inhibits the sodium-plus-potassium-activated adenosinetriphosphatase (ATPase) and potassium-activated p-nitrophenylphosphatase (NPPase) activities of microsomal fractions from electric organ, rat kidney, and rat brain. In the presence of 3 mM MgC12 and 3 mM ATP, the concentrations of PbC12 producing half-maximal inhibition of the ATPase from these tissues are 4 X 10(-6) M, 20 X 10(-6) M, and 55 X 10(-6) M, respectively. The corresponding values for inhibition of the NPPase are 10(-6) M, 53 X 10(-6) M, and 22 X 10(-6) M. PbC12 also stimulates the phosphorylation by [gamma-32P]ATP of a microsomal protein from all three tissues in the absence of added sodium ion. This reaction was extensively studied with electroplax microsomes. In common with the well-known Na+-dependent phosphorylation of (Na+ + K+)-ATPase, the Pb2 -dependent reaction is inhibited by ouabain, specific for ATP, dependent on Mg2+, and yields and acid-stable phosphoprotein with a molecular weight of 98,000 in sodium dodecylsulfate. The Pb2+-dependent phosphoprotein, however, is not sensitive to K+. These observations are pertinent to the biochemistry and toxicity of inorganic lead in tissues and to the molecular mechanism of the cation transport enzyme.
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PMID:Lead actions on sodium-plus-potassium-activated adenosinetriphosphatase from electroplax, rat brain, and rat kidney. 19 30

Mitoplasts, that is, mitochondria freed from their outer membranes, were prepared from pig heart. Sonication induced an inversion of these mitoplasts, giving inside-out vesicles. Added cytochrome c can be bound much better to mitoplasts than to sonicated vesicles; addition of trypsin increased adenosinetriphosphatase (ATPase) (ATP phosphohydrolase; EC 3.6.1.3) activity of sonicated vesicles without significantly affecting that of the mitoplasts. Since the site of fixation of cytochrome c was located on the outer side of the inner mitochondrial membrane and since the protein inhibitor of the mitochondrial ATPase is present on the inner face of the inner membrane and is very sensitive to trypsin, it can be concluded that mitoplasts are mainly oriented as normal mitochondria while sonicated vesicles are mainly inverted. Trypsin treatment can abolish the oligomycin sensitivity of ATPase activity of either mitoplasts or sonicated vesicles. However, trypsin induced the solubilization of the soluble F(1)-ATPase of sonicated vesicles while the ATPase activity remained with the mitoplasts after trypsin action. Therefore, trypsin destroyed the oligomycin effect by rupturing the liaison between F(1) and the membrane in sonicated vesicles. On the other hand, the effect of trypsin on mitoplasts must be attributed to the hydrolysis of a protein located near the outer surface of the inner membrane that is at least structurally involved in the oligomycin sensitivity of the ATPase complex.
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PMID:Location of protein(s) involved in oligomycin-induced inhibition of mitochondrial adenosinetriphosphatase near the outer surface of the inner membrane. 20 Sep 6

Inhibition of adenosinetriphosphatase (ATPase) by vanadium pentoxide (dissolved in water or in sodium hydroxide solution) was studied in microsomal fractions and tissue homogenates of kidney, brain, and heart of several species, including humans (kidney only). In some preparations vanadium was found to be the most potent inhibitor of Na+ + K+ATPase activity so far reported. Concentrations of vanadium causing 50 percent inhibition of Na+ + K+ATPase activity ranged from 6 x 10(-8) to 5 x 10(-7) M in microsomal fractions and from 2 x 10(-7) to 1 x 10(-6) M in tissue homogenates. Renal and cardiac enzymes were more sensitive to vanadium than the brain enzyme, a phenomenon independent of enzyme specific activity. The enzyme in tissue homogenates was more resistant to vanadium than the microsomal enzyme derived from the same tissues, suggesting a presence in tissues of protective agents. Mg2+ ATPase, which contaminated the enzyme preparations to a variable degree, was 1,000-10,000 times more resistant to vanadium than was Na+ + K+ATPase. More detailed studies on the mechanism of inhibition were performed with dog and human kidney enzymes. The reversible nature of the inhibition was suggested by the fact that fractional inactivation of Na+ + K+ATPase by vanadium was independent of enzyme protein concentrations. The inhibitory effect was reduced by Na+ and increased by K+ or Mg2+. ATP alone, but not MgATP, antagonized the inhibition. This could mean that vanadium inhibits the Na+ + K+ATPase at the site activated by Na+, and that ATP protects the enzyme either by binding vanadium or by competing for a mutual receptor on the enzyme. The inhibition was reduced by bovine serum albumin, probably binding vanadium. The inhibition was also diminished by reducing agents, ascorbic acid and citric acid.
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PMID:Inhibition by vanadium of sodium and potassium dependent adenosinetriphosphatase derived from animal and human tissues. 21 60

Norepinephrine added in vitro to nerve ending membranes from rat cerebral cortex stimulates the activity of (Na+, K+) adenosinetriphosphatase (ATPase) only in the presence of the soluble brain fraction. In its absence norepinephrine inhibits the enzyme. (Mg2+)ATPase also showed stimulation by norepinephrine in the presence of the soluble fraction, but of lesser magnitude. The activation of (Na+, K+)ATPase by norepinephrine is not reproduced by cyclic AMP and is not antagonized by either alpha- or beta-adrenergic blocking agents. These results suggest that the stimulation caused by norepinephrine is a direct effect on the enzyme and is not mediated by cyclic AMP or adrenergic receptors.
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PMID:Regulation of (Na+, K+) adenosinetriphosphatase of nerve ending membranes: action of norepinephrine and a soluble factor. 21 46

Na +, K + -adenosinetriphosphatase (Na +, K + -ATPase) activity was decreased in liver plasma membranes from rats in which cholestasis had been induced by i.v. administration of sodium taurolithocholate (5 mumoles/100 g b. wt). Incubation of liver plasma membranes with taurolithocholate (10--1300 muM) caused significant and dose dependent reductions of Na +, K + -ATPase activity at taurolithocholate concentrations above 100 muM. These findings lend support to the hypothesis that cholestasis induced by monohydroxy bile acids is at least partially the result of an inhibition of hepatic Na +, K + -ATPase activity.
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PMID:Inhibition of hepatic Na +, K + -adenosinetriphosphatase in taurolithocholate-induced cholestasis in the rat. 22 96

The activity of Na+, K+-activated adenosinetriphosphatase and the uptake of a potassium analog, rubidium, were found to be similar in cerebral microvessels and choroid plexus when measured in vitro. This similarity suggests that sodium and potassium concentrations in the nascent brain extracellular fluid are determined by the same active process that regulates their concentration in nascent cerebrospinal fluid. The brain microvessels may thereby play on active role in brain potassium homeostasis and brain extracellular fluid formation.
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PMID:Cerebral vessels have the capacity to transport sodium and potassium. 22 60

The stability of the sodium- and potassium-activated adenosinetriphosphatase (Na,K-ATPase) of the electric eel, Electrophorus electricus, was studied in five detergents in an effort to establish conditions for reconstitution of this membrane protein into defined phospholipids. The Na,K-ATPase activity of purified electric organ membranes as well as the ATPase is stable for at least 1 month of storage at 0 degrees C in the absence of detergents. At low concentrations of detergents, the enzyme is also stable for several days, but irreversible inactivation occurs rapidly as the detergent concentration is further increased. This inactivation begins at well-defined threshold concentrations for each detergent, and these concentrations generally occur in the order of the detergent critical micelle concentrations. Increasing the concentration of the electric organ membranes causes a linear increase in the inactivation threshold concentrations of Lubrol WX, deoxycholate, and cholate. The onset of inactivation evidently occurs when the mole fraction of detergent associated with the membrane lipids reaches a critical value in the narrow range of 0.2-0.4, in contrast to the large differences in the bulk concentrations of these detergents. The eel Na,K-ATPase is more sensitive to detergents than the sheep kidney enzyme.
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PMID:Detergent inactivation of sodium- and potassium-activated adenosinetriphosphatase of the electric eel. 22 45

A somatic cell mutant (CR1) of the Chinese hamster ovary cell line (CHO-K1) that is defective in the regulation of cholesterol biosynthesis can be grown under conditions in which plasma membranes from these cells display various cholesterol contents and acyl chain order parameters. The (Na+ + K+)-stimulated adenosinetriphosphatase (ATP phosphohydrolase, EC 3.6.1.3) from these cells was shown to vary in activity by a factor of 10 as the order parameter was varied, and the activity exhibited an exponential dependence on this parameter. Under these conditions the number of Na+,K+-ATPase molecules was shown to remain constant by affinity labeling with [gamma-32P]ATP in the absence of Na+. Control experiments showed that alteration in cholesterol content without change in order parameter did not result in altered enzyme activity. It is concluded that, under our conditions, the rate of catalysis by the Na+,K+-ATPase is determined by the order parameter. These studies suggest a physical mechanism by which variation of membrane lipid composition or other factors that determine membrane lipid acyl chain order parameter can result in variation in membrane enzyme activity.
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PMID:Rate limitation of (Na+ + K+)-stimulated adenosinetriphosphatase by membrane acyl chain ordering. 22 69


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