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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transverse cryostat sections of skeletal muscle were fixed in a solution containing 1.5% glutaraldehyde and 1.5% sulfosalicylic acid and stained in a solution containing equal volumes of 3% hydrogen peroxide and 50% ethanol saturated with o-tolidine. Myoglobin in the sarcoplasm of muscle fibers was precipitated and stained blue. Applicability of this method to cryostat sections, without glutaraldehyde fixations prior to freezing, allowed the myoglobin content of individual muscle fibers to be correlated with other histochemical characteristics of the same fibers seen in serial sections. In the dark red bovine sternomandibularis muscle, fibers with weak adenosine triphosphatase (ATPase) and strong succinate dehydrogenase (SDH) activity always exhibited strong myoglobin staining. An equal degree of staining was found in many fibers with strong ATPase and intermediate to strong SDH activity. Fibers with strong ATPase and weak SDH activity were less strongly stained than the preceding types.
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PMID:A method for myoglobin in cryostat sections of muscle by precipitation with sulfosalicylic acid. 9 25

A particulate subcellular fraction from Escherichia coli K-12 induced in anaerobic sn-glycerol 3-phosphate (G3P) dehydrogenase and fumarate reductase can catalyze under anaerobic conditions the transfer of hydrogens from G3P to fumarate, with attendant generation of high-energy phosphate. The phsophorylation process is more sensitive than the transhydrogenation process to inhibition by the detergent Triton X-100. The same is true with respect to sensitivity to sodium azide, carbonyl cyanide m-chlorophenylhydrazone and N,N'-dicyclohexylcarbodiimide. Such a preparation derived from cells with beta-galactoside permease can accumulate thiomethyl beta-D-galactoside anaerobically, and the accumulation can be stimulated twofold by adding G3P and fumarate. Mutants lacking the membrane-associated Mg2+-dependent adenosine triphosphatase cannot grow anaerobically on glycerol with fumarate as the hydrogen acceptor, although they can grow aerobically on glycerol alone.
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PMID:Anaerobic energy-yielding reaction associated with transhydrogenation from glycerol 3-phosphate to fumarate by an Escherichia coli system. 12 85

Oral heavy water (D20) administration and enzymatic changes were studied in rat testis. D20 caused marked gradual decrease in the weight of the body as well as the testes throughout the treatment interval ranging from 1 to 6 weeks. Following D20 oral administration, an overall marked fall in the activity of acid phosphatase and glucose-6-phosphatase was seen. However,, the activity of lactic and succinic dehydrogenases, alkaline posphatase, and adenosine triphosphatase increased following treatment. These results suggest on altered metabolism of the testes in response to D20 administration and corroborate the view that biological systems do discriminate between hydrogen and deuterium.
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PMID:Oral D2O administration and enzymatic changes in rat testis. 13 64

The transduction of energy through biological membranes was investigated in Escherichia coli strains defective in the ATP synthetase complex. Everted vesicles prepared from strains containing an uncA or uncB mutation were compared with those of the parental strain for their ability to couple energy derived from the oxidation of substrates by the electron transport chain or from the hydrolysis of ATP by the Mg2+-adenosine triphosphatase, as measured by the energy-dependent quenching of quinacrine fluorescence or the active transport of 45Ca2+. Removal of the Mg2+-adenosine triphosphatase from membranes derived from the parental or an uncA strain caused a loss of energy-linked functions and a concomitant increase in the permeability of the membrane for protons. Proton impermeability was restored by treatment with N,N'-dicyclohexylcarbodiimide. When membranes of the uncB strain were treated in a similar manner, there was no loss of respiratory-driven functions, nor was there a change in proton permeability. These observations suggest that the uncB mutation specifically results in alteration of an intrinsic membrane protein channel necessary for the generation of utilzation of the electrochemical gradient of protons by that complex. Loss of the function of the proton channel is believed to prevent the transduction of energy through the ATP synthetase complex.
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PMID:Energy transduction in Escherichia coli: physiological and biochemical effects of mutation in the uncB locus. 14 32

The properties of Alcaligenes eutrophus ATPase (adenosine triphosphatase) were investigated by using subcellular fractions prepared from cells growing in exponential and synchronous cultures. Both the soluble and membrane-bound forms of the ATPase were inhibited non-competitively (K(i) 142mum) by Nbf-Cl (4-chloro-7-nitrobenzofurazan), whereas only the membrane-bound enzyme was inhibited (non-competitive; K(i) 750mum) by NN'-dicyclohexylcarbodi-imide. Neither the activity of the ATPase nor its sensitivity to these two inhibitors varied during exponential growth. However, marked variations in ATPase activity were observed during synchronous growth, which were characterized by maxima at approx. 0.4 and 0.9 of a cell cycle and minima at approx. 0.1 and 0.6 of a cycle. Sensitivity to Nbf-Cl and NN'-dicyclohexylcarbodi-imide also varied during the cell cycle; maximum inhibition by the former occurred at approx. 0.4 and 0.9 of a cell cycle, whereas maximum inhibition by the latter was located at approx. 0.1 and 0.6 of a cell cycle. Proton conductance by whole cells was also periodic during the cell cycle, the lowest rates occurring at approx. 0.15 and 0.55 of a cycle and the highest rates at approx. 0.4 and 0.9 of a cycle, but -->H(+)/O quotients for the oxidation of endogenous substrates remained relatively constant and indicated the presence of four proton-translocating respiratory segments throughout the cell cycle. These results are discussed in terms of ATPase and respiratory-chain structure and function during the cell cycle of Alcaligenes eutrophus.
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PMID:The properties of adenosine triphosphatase from exponential and synchronous cultures of Alcaligenes eutrophus H16. 14 38

Hydrogenase and the adenosine 5'-triphosphate (ATP) synthetase complex, two enzymes essential in ATP generation in Methanobacterium thermoautotrophicum, were localized in internal membrane systems as shown by cytochemical techniques. Membrane vesicles from this organism possessed hydrogenase and adenosine triphosphatase (ATPase) activity and synthesized ATP driven by hydrogen oxidation or a potassium gradient. ATP synthesis depended on anaerobic conditions and could be inhibited in membrane vesicles by uncouplers, nigericin, or the ATPase inhibitor N,N'-dicyclohexylcarbodiimide. The presence of an adenosine 5'-diphosphate-ATP translocase was postulated. With fluorescent dyes, a membrane potential and pH gradient were demonstrated.
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PMID:Chemiosmotic coupling in Methanobacterium thermoautotrophicum: hydrogen-dependent adenosine 5'-triphosphate synthesis by subcellular particles. 16 Apr 8

Omeprazole is a new hydrogen-potassium adenosine triphosphatase antagonist with indications for severe reflux esophagitis and Zollinger-Ellison syndrome. Side effects involving the liver have consisted of minimal elevations of hepatocellular enzymes with higher dosages. We present what we believe is the first reported case of fulminant hepatic failure related to omeprazole.
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PMID:Fulminant hepatic failure related to omeprazole. 155 42

Murine autoimmune gastritis, induced by neonatal thymectomy, bears a striking similarity in pathology to the human autoimmune disease, pernicious anemia. Autoantibodies to parietal cells are found in both murine and human diseases. Monoclonal immunoglobulin G autoantibodies, obtained from neonatally thymectomized mice, have previously been shown to recognize two groups of gastric parietal cell antigens. In the present study, it is shown that two of these monoclonal autoantibodies, designated 1H9 and 2B6, are directed against the alpha subunit and beta subunit, respectively, of the gastric hydrogen-potassium-stimulated adenosine triphosphatase (H+,K(+)-ATPase; proton pump). Monoclonal antibody 1H9 showed reactivity by immunoblotting with a 95-kilodalton component of dog gastric tubulovesicular membranes and with a fusion protein containing the hydrophilic domain of the alpha subunit of the H+,K(+)-ATPase. Monoclonal antibody 2B6 reacted by immunoblotting with the 60-90-kilodalton glycoprotein (beta subunit) of the tomato lectin-purified dog H+,K(+)-ATPase and with the 60-90-kilodalton autoantigen purified with human parietal cell autoantibodies. Monoclonal antibody 2B6 also reacted with the deglycosylated 35-kilodalton core protein of the tomato lectin-purified 60-90-kilodalton beta subunit and of the purified 60-90-kilodalton autoantigen. Parietal cell autoantibody-positive sera from 20 mice with experimentally induced gastritis showed reactivity predominantly with the alpha and/or beta subunit of the gastric H+,K(+)-ATPase. Therefore, it is concluded that the major molecules targeted by parietal cell autoantibodies from mice with neonatal thymectomy-induced murine autoimmune gastritis and from humans with pernicious anemia are identical.
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PMID:The parietal cell autoantigens recognized in neonatal thymectomy-induced murine gastritis are the alpha and beta subunits of the gastric proton pump [corrected]. 164 25

Renal hydrogen ion excretion increases with chronic acid loads and decreases with alkali loads. We examined the mechanism of adaptation by analyzing vacuolar proton-translocating adenosine triphosphatase (H+ ATPase) 31-kD subunit protein and mRNA levels, and immunocytochemical distribution in kidneys from rats subjected to acid or alkali loads for 1, 3, 5, 7, and 14 d. Acid- and alkali-loaded rats exhibited adaptive responses in acid excretion, but showed no significant changes in H+ ATPase protein or mRNA levels in either cortex or medulla. In contrast, there were profound adaptive changes in the immunocytochemical distribution of H+ ATPase in collecting duct intercalated cells. In the medulla, H+ ATPase staining in acid-loaded rats shifted from cytoplasmic vesicles to plasma membrane, whereas in alkali-loaded rats, cytoplasmic vesicle staining was enhanced, and staining of plasma membrane disappeared. In the cortical collecting tubule, acid loading increased the number of intercalated cells showing enhanced apical H+ ATPase staining and decreased the number of cells with basolateral or poorly polarized apical staining. The results indicate that both medulla and cortex participate in the adaptive response to acid and alkali loading by changing the steady-state distribution of H+ ATPase, employing mechanisms that do not necessitate postulating interconversion of intercalated cells with opposing polarities.
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PMID:Expression and distribution of renal vacuolar proton-translocating adenosine triphosphatase in response to chronic acid and alkali loads in the rat. 182 94

Hydrogen ion secretion in the kidney is thought to be mediated in part by an N-ethylmaleimide (NEM)-sensitive proton-translocating adenosine triphosphatase (ATPase). This enzyme has been found throughout the nephron, but it has not been completely characterized enzymatically in the rat collecting duct. In the present study we characterized the NEM-sensitive ATPase from microdissected cortical (CCT) and medullary (MCT) collecting tubules of the rat nephron. At optimum conditions, NEM-sensitive ATPase activity was the same in both tubule segments: activity was 275.6 +/- 18.6 pmol/mm/h in the CCT and 280.3 +/- 35.2 pmol/mm/h in the MCT (n = 23, NS). ATP sensitivity was greater in CCT than in MCT, and in the former guanosine triphosphate was able to partially support enzyme activity. Maximal enzyme inhibition with NEM occurred at a lower concentration in CCT as compared to MCT. At pH 7.0 in MCT enzyme activity was approximately one half that seen at pH 7.4; in MCT and CCT, the pH optimum was 7.4. The temperature optimum in both segments was between 37 and 42 degrees C. Enzyme activity in CCT and MCT was linear to 30 min and proportional to tubule length. These results demonstrate that there are important differences in the NEM-sensitive ATPase isolated from two segments of rat collecting duct, and raise the possibility that enzyme heterogeneity may exist.
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PMID:Characterization of the N-ethylmaleimide-sensitive ATPase in rat cortical and medullary collecting tubule. 184 Feb 79


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