Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sodium- and potassium-dependent adenosine triphosphatase (Na+--K+-ATPase) has been demonstrated in the branchial heart appendage (pericardial gland) of Sepia officinalis L. by biochemical, cytochemical and autoradiographical methods. The biochemical data indicate the presence of Na+--K+-ATPase, judging from the potassium dependency and, with some restrictions, the inhibition by ouabain. Cytochemically and autoradiographically, the enzyme could be localized on the cytoplasmic surfaces of the lateral plasma membranes and the basal membrane infoldings (basal labyrinth) of the folded epithelium of the branchial heart appendage. The pdocytes of the peripheral zone of the organ reacted negatively. In addition to the Na+--K+-ATPase, a magnesium-activated adenosine triphosphatase (Mg2+-ATPase) was demonstrated in the folded epithelium, localized mainly in the mitochondria but also at the brush border and in the apical intercellular space, whereas a bicarbonate-stimulated ATPase (HCO-3-ATPase) was present only in the mitochondria.
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PMID:Adenosine triphosphatase localization in the branchial heart appendage of Sepia officinalis L. (Cephalopoda). 23 Jan 67

To study whether a proton pump is an integral part of the mechanism responsible for secretin-dependent biliary secretion of HCO-3 ions, the proton pump inhibitor N,N'-dicyclohexylcarbodiimide (DCCD) was systemically administered to six anesthetized, secretin-infused pigs. Because biliary HCO-3 secretion varies with arterial pH, secretion rate was measured at several different arterial pH values, before and after DCCD (25 mumol/kg). At arterial pH 7.45, bile flow was 2.1 (1.6-2.9) ml/min, and HCO-3 secretion was 224 (157-311) mumol/min. DCCD reduced bile flow and HCO-3 secretion by 30% and 40%, respectively, independent of arterial pH. In contrast, bile acid secretion, 46 (41-59) mumol/min, was not changed by DCCD. The hepatic adenosine triphosphatase (ATP) level, 2.0 (1.8-2.1) mumol/g wet tissue, was not changed by DCCD. DCCD (10(-4) mol/l) affected neither Na,K-ATPase nor carbonic anhydrase activities in separate in vitro assay systems. The reduction in biliary HCO-3 secretion induced by the proton pump inhibitor DCCD may indicate that a proton pump is integrated into the mechanism responsible for secretin-dependent biliary secretion of HCO-3.
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PMID:DCCD (N,N'-dicyclohexylcarbodiimide) inhibits biliary secretion of HCO-3. 303 16

Transport systems involved in proximal tubule HCO-3 reabsorption were examined in disaggregated renal cortical tubules from rabbits with metabolic alkalosis. The acid-base disorder was induced by first treating the animals with furosemide, and then maintaining them on low Cl--high HCO-3 diets. On this regimen, the rabbits had increases in blood pH and total CO2 values and decreases in serum K+ concentrations. Urine Cl- concentrations were less than 15 mEq/L in all cases. Na+-H+ exchange was evaluated by incubating tubules in rotenone in an Na+-free medium to deplete them of Na+ and adenosine triphosphate. Then the tubules were resuspended in media containing 65 or 12.5 mEq/L Na+ at either pH 7.1 or pH 7.6. The rise in cell pH estimated by dimethadione distribution was taken as a measure of Na+-H+ exchanger activity. At the high incubation pH, Na+-H+ exchanger activity appeared to be the same in tubules taken from alkalotic rabbits compared with those prepared from normal rabbits. At the low incubation pH, the activity of this transport system appeared to be depressed by 40% to 50% in alkalosis, with kinetics that suggested a decreased Vmax for the exchanger. Na+-independent H+ transport, presumably reflecting activity of an H+-adenosine triphosphatase, was evaluated by preincubating tubules in a Na+-free medium in the presence of ouabain, and then sequentially exposing them to and removing them from a solution containing 20 mmol/L NH4Cl.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Proximal tubule hydrogen ion transport processes in diuretic-induced metabolic alkalosis. 400 20

Cytochemical techniques were used to demonstrate, with appropriate controls, alkaline phosphatase and HCO-3-activated adenosine triphosphatase (ATPase) in rat duodenal brush border microvillus membranes. Intense activity of ecto-alkaline phosphatase activity was demonstrated with 2-glycerophosphate as substrate. Although biochemical assays suggested that L-phenylalanine inhibited both alkaline phosphatase and HCO-3-activated ATPase, cytochemical studies indicated that there was marked inhibition of alkaline phosphatase revealing a specific HCO-3-activated ATPase on the inner aspect of the microvillus membrane. While it is tempting to suggest that this HCO-3-activated ATPase is implicated in active bicarbonate secretion by the duodenum, decisive identification is not yet possible.
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PMID:Cytochemical studies on the localization of alkaline phosphatase and HCO-3-activated adenosine triphosphatase in the brush border membrane of rat duodenal enterocytes. 614 Feb 47

Anthropogenic sources increase freshwater salinity and produce differences in constituent ions compared with natural waters. Moreover, ions differ in physiological roles and concentrations in intracellular and extracellular fluids. Four freshwater taxa groups are compared, to investigate similarities and differences in ion transport processes and what ion transport mechanisms suggest about the toxicity of these or other ions in freshwater. Although differences exist, many ion transporters are functionally similar and may belong to evolutionarily conserved protein families. For example, the Na+ /H+ -exchanger in teleost fish differs from the H+ /2Na+ (or Ca2+ )-exchanger in crustaceans. In osmoregulation, Na+ and Cl- predominate. Stenohaline freshwater animals hyperregulate until they are no longer able to maintain hypertonic extracellular Na+ and Cl- concentrations with increasing salinity and become isotonic. Toxic effects of K+ are related to ionoregulation and volume regulation. The ionic balance between intracellular and extracellular fluids is maintained by Na+ /K+ -adenosine triphosphatase (ATPase), but details are lacking on apical K+ transporters. Elevated H+ affects the maintenance of internal Na+ by Na+ /H+ exchange; elevated HCO3- inhibits Cl- uptake. The uptake of Mg2+ occurs by the gills or intestine, but details are lacking on Mg2+ transporters. In unionid gills, SO42- is actively transported, but most epithelia are generally impermeant to SO42- . Transporters of Ca2+ maintain homeostasis of dissolved Ca2+ . More integration of physiology with toxicology is needed to fully understand freshwater ion effects. Environ Toxicol Chem 2017;36:576-600. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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PMID:Toxicological perspective on the osmoregulation and ionoregulation physiology of major ions by freshwater animals: Teleost fish, crustacea, aquatic insects, and Mollusca. 2780 48