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)

The teleostean gill is characterized by an exceptionally low permeability to water. Water moves along the osmotic gradient across the gill, being gained in fresh water and lost in sea water. Coupling of water movement to solute movement has not been reported. In fresh water, the gill is the site of independent active uptake of sodium and chloride. Na+ uptake is coupled to H+ or NH4+ excretion, Cl- uptake to HCO3- excretion. Amiloride blocks sodium transport and thiocyanate inhibits the chloride pump. In sea water, sodium and chloride exchanges across the gill are about 100 times faster than in fresh water, up to 100% of the internal sodium or chloride being exchanged per hour. Chloride is actively excreted, while sodium movement may well be passive. The chloride pump is associated with a mechanism for Na/K exchange; both pump and Na/K exchange are blocked by thiocyanate and possibly by ouabain. Three enzymes are involved in the ionic pumps: carbonate dehydratase (EC 4.2.1.1; carbonic anhydrase), sodium/potassium-stimulated adenosine-triphosphatase (EC 3.6.1.3, ATPase) and anion-stimulated ATPase. Specialized cells ('chloride cells') are presumably the site of the active transport.
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PMID:Transport of ions and water across the epithelium of fish gills. 0 38

In vitro inhibition of adenosine triphosphatase and carbonic anhydrase by several radiographic contrast media and other compounds was measured. The concentrations required for 50% inhibition were, in general, similar to those obtained for other enzymes. The effect of methylglucamine could not be determined for either enzyme because of interference with the assays.
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PMID:Inhibition of adenosine triphosphatase and carbonic anhydrase by contrast media. 12 74

The disulfonic stilbene (4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene) is found to be more potent than acetazolamide as an anion transport inhibitor in the turtle bladder, but less potent than acetazolamide as a carbonic anhydrase inhibitor. The anion-dependent (HCO-3,Cl-) moiety of the short-circuiting current is eliminated by 4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene, but only after its addition to the serosal bathing fluid. Whereas 4-acetamido-4'-isothiocyano-2,2'-disulfonic stilbene has no effect on Na+ transport across the bladder, it is more potent than ouabain as an inhibitor of microsomal (Na+ + K+)-ATPase of both turtle bladder and eel electric organ.
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PMID:Effects of 4-acetamido-4'-isothiocyano-2,2-disulfonic stilbene on ion transport in turtle bladders. 12 57

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 isolated rectal gland of Squalus acanthias was stimulated to secrete chloride against an electrical and a chemical gradient when perfused in vitro by theophylline and/or dibutyryl cyclic AMP. Chloride secretion was depressed by ouabain which inhibits Na-K-ATPase. Thiocyanate and furosemide also inhibited chloride secretion but ethoxzolamide, a carbonic anhydrase inhibitor, did not. Chloride transport was highly dependent on sodium concentration in the perfusate. The intracellular concentration of chloride averaged 70-80 meq/liter in intact glands, exceeding the level expected at electrochemical equilibrium and suggesting active transport of chloride into the cell. These features suggest a tentative hypothesis for chloride secretion by the rectal gland in which the uphill transport of chloride into the cytoplasm is coupled through a membrane carrier to the downhill movement of sodium along its electrochemical gradient. The latter is maintained by the Na-K-ATPase pump while chloride is extruded into the duct by electrical forces.
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PMID:Mechanism of active chloride secretion by shark rectal gland: role of Na-K-ATPase in chloride transport. 14 96

The characteristics of the anion-sensitive Mg2+-ATPase activity of the rabbit erythrocyte have been studied in a lyophilized ghost preparation. The enzyme appears to be different from the anion-sensitive Mg2+-ATPase activity of other tissues in many parameters, such as optimal pH, effects of various anions, oligomycin sensitivity and effects of Triton X-100. The enzyme is insensitive towards inhibition by irreversibly bound 4,4'-diisothiocyano-dihydrostilbene-2,2'-disulfonic acid (H2DIDS). This excludes a relationship between the enzyme and the "band 3" protein, which is thought to be involved in the anion exchange over the erythrocyte membrane. From the effects of ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA), CaCl2, chlorpromazine and ruthenium red it is concluded that the enzyme activity does not represent a separate entity but is part of the (Ca2+ + Mg2+)-ATPase system of the erythrocyte membrane. A reported stimulatory effect of carbonic anhydrase is attributed to a contamination of the carbonic anhydrase preparation by calcium and/or (Ca2+ + Mg2+)-ATPase activator protein.
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PMID:Is there a plasma membrane-located anion-sensitive ATPase? III. Identity of the erythrocyte enzyme with (Ca2+ + Mg2+)-ATPase. 14 18

1. Gill, kidney and blood levels of acetazolamide-sensitive esterase (carbonic anhydrase) activity were estimated at acclimation temperature and at a common temperature (25 degrees C) in rainbow trout acclimated to 2, 10 and 18 degrees C. Plasma levels of sodium, potassium and chloride were also examined for possible acclimatory variations. 2. Plasma sodium and chloride levels, and the sodium:chloride ratio were unaffected by thermal acclimation; potassium concentrations were significantly elevated at 18 degrees C. 3. Significant, but modest changes in renal and branchial carbonic anhydrase activity were observed under physiologically realistic incubation temperature conditions. Blood carbonic anhydrase activity was sharply elevated at higher acclimation temperatures. 4. The data are discussed in relation to the hypothesis that carbonic anhydrase in this relatively stenothermal freshwater salmonid, through its intimate association with the coupled HCO-3/CL- and H+ +NH+4/Na+ exchange systems may provide for relatively thermostable basal rates of sodium and chloride uptake from the medium and recovery from urine. The renal, and more notably the branchial (Na+/K+)-stimulated ATPase systems, and erythrocytic carbonic anhydrase may then serve primarily as high-temperature amplifiers of sodium and chloride recruitment respectively.
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PMID:Carbonic anhydrase (acetazolamide-sensitive esterase) activity in the blood, gill and kidney of the thermally acclimated rainbow trout, Salmo gairdneri. 14 85

In this study, enzyme activities of the pancreatic appendages of the ductus hepatoPancreas (the so-called "pancreas") in Sepia officinalis L. have been demonstrated by light and electron micicroscopical methods: Malate dehydrogenase, monoamine oxidase, acid phosphatase, beta-glucuronidase, adenosine triphosphatase and carbonic anhydrase were shown by the former, and monoamine oxidase, catalase, glutamic oxalacetic transaminase, choline esterase (non-specific), alkaline phosphatase, acid phosphatase and carbonic anhydrase by the latter technique. The correlation between enzyme activity and distribution, and the presumed function of the two pancreatic epithelia is discussed.
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PMID:The localization of enzyme activities in the pancreatic appendages of Sepia officinalis L. (Cephalopoda). 15 95

The development of (Na+ + K+) ATPase, carbonic anhydrase and HCO3--stimulated ATPase activity was studied in developing rat brain in vivo, and in primary astrocyte cultures from 1--3-day-old rat brain as a function of increasing cell growth. The primary cultures showed an increase in all the above enzyme activities during cell growth, with time courses which were qualitatively similar to their development in vivo. Cell cultures grown separately from the cerebellum plus brain stem regions showed greater carbonic anhydrase activity than cerebral cultures over the entire 4-week growth period, corresponding to development of this activity in these same regions in vivo, HCO3-stimulated ATPase activity was slightly greater in cerebellar cultures and (Na+ + K+) ATPase activity was greater in cerebral cultures up to the second week of growth, resembling development of the same enzyme activities in vivo. C6 glioma and neuroblastoma cells showed no and 10-fold lower carbonic anhydrase activities respectively, compared to the primary astrocyte cultures. Addition of 1 mM N6-2'-O-dibutyryladenosine-3',5'-monophosphate (DBcAMP) in the presence of serum caused marked formation of cellular processes and increased carbonic anhydrase and (Na+ + K+) ATPase activity. Maximum effects were found 2 h after addition of 1 mM DBcAMP and thereafter declined. In the absence of serum such effects persisted for at least 24 h. Electron microscope studies showed large numbers of microtubule (approximately 20 nm diameter) and filamentous structures (less than or equal to 10 nm diameter) in the cytoplasm, which showed changes in distribution in cells treated with DBcAMP. This study suggests that the increase in ATPase and carbonic anhydrase activities in rat brain with increasing age may be in part a reflection of proliferation and development of astroglia cells. Together with the morphological data, it also provides additional evidence that primary cultures derived from neonatal rats may closely resemble developing astroglia in vivo.
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PMID:Enzymatic and morphological properties of primary rat brain astrocyte cultures, and enzyme development in vivo. 20 76

The isolated rectal gland of the spiny dogfish is a unique model for the study of active chloride transport. The gland is stimulated to secrete chloride agains an electrical and a chemical gradient when perfused in vitro by theophylline and/or dibutyryl cyclic AMP. Chloride secretion is depressed by ouabain which inhibits Na-K-ATPase. Thiocyanate and furosemide also inhibit chloride secretion but ethoxolamide, a carbonic anhydrase inhibitor, does not. Chloride transport is highly dependent on sodium concentration in the perfusate. The intracellular concentration of chloride in intact glands exceeds the level expected at electrochemical equilibrium, suggesting active transport of chloride into the cell. These features suggest a general hypothesis for chloride secretion in which the uphill transport of chloride into the cytoplasm is coupled through a membrane carrier to the downhill movement of sodium along its electrochemical gradient. The latter is maintained by the Na-K-ATPase pump while chloride is extruded into the duct by electrical forces.
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PMID:Active chloride transport powered by Na-K-ATPase in shark rectal gland. 21 Sep 93


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