Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

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

Recent studies have demonstrated that chronic potassium loading increases Na-K-ATPase specific activity in kidney tissue and suggest that this enzyme plays a role in renal potassium adaptation. Studies of fluid and electrolyte movement, potential difference (PD), AND Na-K-ATPase were performed in colon and jejunum of the rat in order to further characterize the relationship of Na-K-ATPase to potassium secretion. Experimental rats fed 2.6 meq K/gm diet for 7 days were compared to a control group fed 0.13 meq K/gm. In the colon, chronic potassium loading increased potassium secretion from 0.8 +/- 0.2 to 3.9 +/- 0.9 mueq/min per g tissue (P less than 0.01) and PD from 27 +/- 5.0 to 54 +/- 2.6 mV (P less than 0.001), lumen negative, as Na-K-ATPase increased from 5.0 +/- 0.5 to 11.4 +/- 1.0 muM Pi/mg protein per h (P less than 0.001). In contrast, there was no change in PD, potassium movement, or Na-K-ATPase in the jejunum of potassium-loaded rats. Colonic movement of water, sodium, and chloride was similar in the control and potassium-loaded rats. These results indicate that increased Na-K-ATPase is associated with both increased PD and increased potassium secretion in the colon and provide additional evidence suggesting that Na-K-ATPase may be important in the control of transepithelial potassium movement.
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PMID:Potassium secretion by colonic mucosal cells after potassium adaptation. 13 7

An electrophilous inhibitor, p-(N,N-di-2-chloroethyl)amino-phenylacetic acid (I), specifically disturbs the mechanism of respiration and phosphorylation coupling in mitochondria. I inhibits respiration and ATPase activity in intact mitochondria and does not affect these processes in mitochondria and submitochondrial particles with partially or completely impaired coupling system. The data obtained show that I inhibits protonophoric function of NADH-ferricianide reductase from submitochondrial particles soluble ATPases from bovine heart and Micrococcus lysodeikticus mitochondria adsorded on octane water interface and has no effect on respective enzymes in water solutions. Cation-transferring enzymes are shown to behave with respect to the inhibitor on lipid water interface like respective enzymes in intact mitochondria, while in water solutions they behave like those in systems with the impaired coupling mechanism. Effect of I on protonophoric function of oligomycin-sensitive ATPase and bacteriorhodopsin plaques isolated from Halobacterium halobium is also studied. It is shown that the precence or the absence of I effect is due to a nature of lipid in the enzymatic complex. I is found also to inhibit specifically the transport of Ca2+ from water to octane in the presence of Ca2+-ATP-ase from rabbit sarcoplasmic reticulum.
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PMID:[Mechanism of action of the specific inhibitor of respiration and phosphorylation in mitochondria--n-(N,N-di-2-chlorethyl)aminophenylacetic acid]. 13 99

Left ventricular myocardia of Goldblatt rats with an average increase in arterial blood pressure to about 200 mm Hg showed a progressive reduction of the Ca-activated specific acotmyosin ATPase activity 4 -12 weeks after the coarctation of one renal artery, as compared with controls of the same age. During the same period, a significant increase in the concentration of contractile proteins was noticeable, whereas the content of nonprotein substances and of water corresponded to the control values. The hydroxyproline concentration, as a measure of the collagen tissue content, increased only after 24 weeks. The time course of the specific ATPase activity was closely parallel to the decrease in the unloaded myocardial shortening velocity, as estimated at the same stage by our group. This is in accordance with the assumption of a fundamental relationship between the two values. The reduced rate of energy turnover and of the shortening velocity is regarded as an adaptive mechanism which, however, has a negative effect in advanced hypertrophy when further diminution takes place. The decrease in the specific enzymatic activity of actomysin is not necessarily linked to a large increase in myocardial mass, but is already apparent at moderate degrees of hypertrophy (34%).
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PMID:Concentration and adenosinetriphosphatase activity on left ventricular actomyosin in Goldblatt rats during the compensatory stage of hypertrophy. 13 1

1. Digitonin treated membrane preparations purified from dog kidney lose their (Na+,K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity, but the K+-phosphatase and Na+-dependent ADP-ATP exchange activities survive and remain ouabain-sensitive. Because the enzyme preparations consist largely of pure (Na+,K+)-ATPase, these effects of digitonin must be intrinsic to the Na+ pump. 2. Concomitant with these enzymatic changes, digitonin treatment alters the sensitivity of the phosphatase and exchange activities to ouabain. 3. Attempts to measure ouabain binding by the usual centrifugation or filtration methods proved unsuccessful. A filtration method involving a double 0.01 mum filter and omitting water washes is necessary to demonstrate ouabain binding. Under these conditions, ouabain binding capacity appears to be unchanged in the presence of digitonin, but the apparent dissociation constant is doubled. 4. Ouabain binding is rendered more reversible by digitonin treatment, since washing filters with water removes a large fraction of bound ouabain without affecting the retention of exchange activity. 5. The double filter method traps essentially all of the ADP-ATP exchange activity on the filter. However, a large and somewhat variable proportion of the K+-phosphatase activity passes through the filter. Sodium dodecyl sulfate polyacrylamide gel analysis of the filtrate shows that a small amount of filtrable protein catalyzed this phosphatase activity at greatly increased turnover rates. Both subunits of the (Na+, K+)-ATPase are present in this latter protein fraction.
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PMID:The measurement of ouabain binding and some related properties of digitonin-treated (Na+,K+)-ATPase. 13 44

Anthroylouabain (AO) was synthesized by reaction of anthracene-9-carboxylic chloride with ouabain. Nuclear magnetic resonance spectroscopy of AO suggests that the anthracene is esterfied to the rhamnose in the glycoside. AO inhibits Na-K ATPase from human red cells, eel electroplax and rabbit and dog kidney with a KI less than 1muM. AO bound to rabbit or dog kidney Na-K ATPase shows enhanced fluorescence and characteristic spectral shifts. AO binding requires Mg and is optimum in the presence of Mg + Pi or MgATP + Na; ouabain prevents AO binding and fluorescence enhancement if added before AO or reverses it if added after AO is bound. Na inhibits AO binding in the presence of Mg + Pi and K inhibits it in the presence of MgATP + Na. AO binding and dissociation rate constants measured by fluorescence agree qualitatively with reported measurements for ouabain, using other methods, although AO shows faster kinetics than ouabain. Dissociation constants obtained from kinetic measurements are 1.5 X 10(-7) and 1.8 X 10(-7) M for the MgATP + Na complex and Mg + Pi complex, respectively. KD from fluorescence titrations is 2.3 X 10(-7) M for the latter. The enzyme has 2-2.5 nmol of AO binding sites/mg of protein. No differences in the fluorescence parameters of the Mg + Pi or MgATP + Na complexes were observed, suggesting that the same enzyme conformation binds AO under both ligand conditions. Comparison of the AO fluorescence parameters in the enzyme with those of model systems suggests that the binding site is hydrophobic and/or viscous and shielded from H2O. The results indicate that AO is a specific fluorescent probe of the cardiac glycoside receptor of the Na-K ATPase. Possible applications are discussed.
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PMID:Anthroylouabain: a specific fluorescent probe for the cardiac glycoside receptor of the Na-K ATPase. 13 37

Ouabain circulating in blood inhibits Na-K-ATPase in the gills of seawater eels at a concentration similar to that necessary for inhibition in vitro. By contrast, a much higher concentration is required when ouabain is applied to the exterior of the gill. Inhibition by external ouabain occurs only when the drug gains access to the circulation of the fish, as evidenced by simultaneous inhibition of Na-K-ATPase in the kidney. These results suggest that the Na-K-ATPase of gill chloride cells faces inward, lining intracytoplasmic tubular channels continuous with the extracellular fluid. Inhibition of gill Na-K-ATPase by ouabain in intact salt water eels results in almost complete inhibition of the efflux of both Na+ and Cl-. The efflux is tritiated water was much less reduced, to 60% of normal. Since chloride is actively transported outward across the gill of seawater teleosts, it is suggested that active chloride transport is coupled to Na-K-ATPase. A neutral sodium chloride carrier is postulated that is energized by the movement of sodium from extracellular fluid down its electrochemical gradient into the chloride cell.
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PMID:Ouabain inhibition of gill Na-K-ATPase: relationship to active chloride transport. 13 54

Purified dicyclohexylcarbodiimide-sensitive ATPase (TF0-F1) from thermophilic bacterium PS3 is composed of a water soluble part with ATP hydrolytic activity (TF1) and a water insoluble moiety (TF0). All of the five subunits (alpha, beta, gamma, delta, and epsilon) of TF1 were isolated. TF1 was reconstituted from the five subunits, which catalyzed an ATP-32Pi exchange and an ATP-driven enhancement of fluorescence of 1-anilinonaphthalene-8-sulfonate, when adsorbed on proteoliposome inlaid with TF0 (TF3-vesicles). Subunit epsilon and/or delta became firmly bound to TF0-vesicles and there was no preferential sequence in the binding. Both subunits were required for binding of the remaining subunits of TF1 to TF0-vesicles, but they did not modify the high H+ -permeability of TF0-vesicles. The addition of gamma but they did not modify the high H+-permeability of TFO-vesicles. The addition of gamma subunit together with epsilon and delta subunits caused a marked decrease of H+ -permeability of TF0-vesicles, similar to that induced by TF1. We conclude tentatively that the epsilon and delta subunits connect TF0 and the other subunits forming a part of a proton pathway, gamma is a gate of proton flow coupled to ATP hydrolysis (or synthesis), and alpha and beta subunits contain the active site for energy transformation. A possible model of subunit structure of TF1 is proposed.
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PMID:Reconstitution of thermostable ATPase capable of energy coupling from its purified subunits. 13 10

The mechanical properties and the activity of the myofibrillar ATPase have been investigated at 21 degrees C on glycerinated back muscle from the water-bug Lethocerus colossicus. When the fibres were held under isometric conditions after stretching them by 0.5--4%, the ATPase required to maintain a given tension increases from 19 to 39 p-moles ATP split for each mg of tension developed as the Ca2+ level is increased from 10(-7) to up to 10(-5) M. The mechanical properties and the ATPase activity have been determined for Ca2+-activated fibres using sinusoidal frequencies of 1--30 HZ and oscillatory amplitudes of 0.5--6% peak-to-peak. In this way the R.M.S. velocity of sinusoidal movement was varied between 0.1-10 mm/sec. The rate of ATP splitting associated with oscillatory tension development, the dynamic tension cost, increases both with Ca2+ and with frequency of oscillation (at 1% peak-to-peak amplitude), becoming as high as four times the isometric value. The oscillatory power output which can be obtained is increased when the Ca2+ level is raised from 10(-7) to 10(-5) M or towards higher amplitudes of oscillation. The chemo-mechanical coupling efficiency increases proportionally with the R.M.S. velocity of muscle movement. In presence of 10(-5) M Ca2+ optimal efficiencies of 5.5--6.2 kcal work per mole ATP split are obtained at R.M.S. velocities of 1.3--2 muscle lengths/sec. The ability of the muscle fibres to perform osciillatory work at the higher frequencies was much reduced at lower Ca2+ levels of 10(-6) or 10(-7) M and the maximal efficiencies never exceeded 2.2 kcal/mole.
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PMID:The chemo-mechanical coupling relation in the oscillatory contraction-relaxation cycles of insect fibrillar muscle. 14 Feb 2

The effect of the hallucinogenic drug harmaline was tested on rat kidney proximal tubular solute and water transport, using in vivo micropuncture and electrophysiological techniques as well as in vitro biochemical techniques. During peritubular application harmaline (5 mmol/l) was found to block net tubular volume absorption reversibly (by 85%) through inhibition of active Na+ transport and possibly active HCO-3 transport. The inhibition was accompanied by a rapid strong depolarization of the tubular cell membranes. As a biochemical equivalent harmaline inhibited the Na+-K+-ATPase and the Mg2+-ATPase of peritubular cell membrane fractions as well as the HCO-3-stimulated ATPase of a brush border membrane fraction with similar kinetics. By studying glucose tracer efflux and by measuring cell membrane potential and conductance changes in response to glucose perfusions, no evidence for a direct effect of harmaline on Na+-glucose (or amino acid) cotransport mechanisms in the brush border could be obtained. The data suggest that harmaline does not specifically compete with Na+ for transport sites. Neither are the cotransport systems in the brush border membrane specifically inhibited, nor could the inhibition of the Na+ pump in the peritubular cell membrane simply result from a competition between harmaline and Na+.
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PMID:The mechanism of action of harmaline on renal solute transport. 14 Mar 66


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