Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly L-lysine, poly L-ornithine, and histone significantly inhibited the iodide uptake by the thyroid slices, as previously reported. These basic polymers diminshed Na, K-ATPase and concomitantly markedly elevated Mg-ATPase activity in the NaI-treated microsomal preparation and the plasma membrane fraction obtained from thyroid. Poly L-glutamic acid, which was noneffetive to the iodide uptake in vitro, did not show such phenomenon. K-dependent p-nitrophenylphosphatase activity which is considered to reflect the terminal step of the reaction sequence of Na, K-ATPase was also inhibited by poly L-lysine. The effects mentioned above of poly L-lysine and other basic polyamino acids on membrane ATPase system were only found in the preparations from thyroid. The inhibitory effect of these reagents on thyroidal iodide uptake was discussed in terms of the change in membrane ATPase activities.
 ...
PMID:Some properties of thyroidal membrane adenosinetriphosphatase and iodide uptake: effects of basic polyamino acids. 13 43

Microsomal preparations from breast muscle of normal and dystrophic chickens are characterized with regard to ultrastructural features, protein composition, Ca2+ transport and ATPase activity. Dystrophic muscle yields a greater microsomal dry weight, with a reduced protein to lipid ratio. This is related to the presence of a considerable number of low density microsomes, in addition to seemingly normal microsomes. The low density microsomes display a reduced number of protein particles on freeze fracture faces. Electrophoretic analysis reveals nearly identical patterns in normal and dystrophic microsomes. Furthermore, normal and dystrophic microsomes sustain equal rates of Ca2+ transport and ATPase, demonstrating an identical protein specific activity. However, the dystrophic microsomes have a lower capacity to retain transported Ca2+. The high yield of low density microsomes with reduced capacity for Ca2+ uptake is attributed to the presence of membranes proliferated in the junctional and tubular sarcomere regions of the dystrophic muscle. It is suggested that proliferation of such membranes accounts for the altered excitation-contraction coupling and cable properties of genetically dystrophic muscle.
 ...
PMID:The involvement of sarcotubular membranes in genetic muscular dystrophy. 13 44

The effects of CdCl2 on adenosine triphosphatase (ATPase) were studied microsomal fractions or tissue homogenates of outer cortex, inner cortex and outer medulla of dog kidney. Cd was found to be an inhibitor of Na+ +K+ Atpase with 150 value of 2.1 to 3.2 X 10(-4) M regardless of type or source of the enzyme preparation tested. Mg++ ATPase was about 10-fold less sensitive to inhibition by Cd than Na+ +K+ ATPase. The inhibition of microsomal NA+ +K+ ATPase from outer medulla was characterized by irreversible kinetics. The inhibitory effect was not altered by varying Na+ or K+ concentrations, but was decreased by disodium ethylenediaminetetracetic acid (EDTA). EDTA was more effective in preventing than in reversing the inhibition. Na+ +K+ ATPase from kidneys of several other mammalian species showed a similar sensitivity to Cd.
 ...
PMID:Inhibition of renal adenosine triphosphatase by cadmium. 13 65

Alcohol tolerance, measured as performance on the tilting plane after ethanol injection (2.5 g/kg body weight i.p.), was examined in the AA strain of rats which voluntarily drink large amounts of alcohol, in the ANA strain which drink very little alcohol, and in ordinary albino rats which consume intermediary amounts of alcohol. The AAs showed the highest innate ethanol tolerance; the ANAs had the lowest innate tolerance. After chronic alcohol administration, both AA and ANA strains increased their tolerance, but the AAs remained superior to the ANAs. The chronic ethanol treatment did not significantly change the (Na+K+) ATPase activity of the crude microsomal fraction of the brains of the strains.
 ...
PMID:An inborn alcohol tolerance in alcohol-preferring rats. The lack of relationship between tolerance to ethanol and the brain microsomal (Na+K+) ATPase activity. 13 33

A study of the intracellular localization of HCO-3-stimulated, SCN--inhibited magnesium-dependent ATPase was performed in gill tissue of the rainbow trout (Salmo irideus), rabbit kidney and rabbit gastric mucosa. Tissue homogenates were subjected to centrifugal fractionation, and the microsomal (60 min 100 000 X g) and light mitochondrial (20 min 20 000 X g) fractions were further fractionated by density gradient centrifugation. Subfractions were characterized by marker enzyme assays and electron microscopic observation. In trout gill indications for an exclusively mitochondrial localization were found. In kidney no definite conclusions could be drawn. In rabbit gastric mucosa initially an apparently non-mitochondrial HCO-3-stimulated ATPase, in addition to a mitochondrial one, was found and its characteristics were studied. Further studies showed that this ATPase also appears to be of mitochondrial origin and probably represents mitochondrial inner membranes. Possible explanations for earlier conflicting reports concerning the localization of this enzyme in gastric mucosa and other tissues are discussed.
 ...
PMID:Is there a plasma membrane-located anion-sensitive ATPase? 13 24

ATP plus Mg2+ plus Na+ supported [3H]ouabain binding to canine left ventricular tissue homogenates and microsomal (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity from the same tissue were measured. A linear relationship was found between the initial velocity of [3H]ouabain binding to tissue homogenates and microsomal (Na+ + K+)-ATPase activity from the same tissue in the presence and absence of in vivo bound digoxin. In vivo bound digoxin reduced both measurements. With tissue from digoxin-free hearts, a linear relationship was also obtained between the initial velocity and the maximum level of [3H]ouabain binding to tissue homogenate. Binding of [3H]ouabain to whole tissue homogenate is a convenient method for estimating (Na+ + K+)-ATPase activity in small left ventricular biopsy samples.
 ...
PMID:Correlation between microsomal (Na+ + K+)-ATPase activity and [3H]ouabain binding to heart tissue homogenates. 13 36

A microsomal preparation with a high ability for Ca2+ uptake has been isolated from pigeon heart. A method of further purification of Ca2+-accumulating system of heart, based on the ability of sarcoplasmic reticulum for the energy-dependent Ca2+ accumulation in the presence of oxalate, has been developed. Upon centrifugation in the gradient of sucrose and KCl concentration the fragments of sarcoplasmic reticulum, rendered "heavy" by calcium oxalate, can be separated from foreign cell membranes. The main component of heart "calcium pump" is Ca2+-dependent ATPase (making up to about 50% of all proteins of the purified reticulum), having a molecular weight of 100.000--105.000. Specific activity of heart Ca2+-ATPase as well as the ability of purified heart sarcoplasmic reticulum for Ca2+ uptake are only slightly less than those of the skeletal muscle reticulum. The data obtained suggest that heart sarcoplasmic reticulum may be efficient for providing heart muscle relaxation.
 ...
PMID:[Isolation of highly active preparations of sarcoplasmic reticulum and Ca2-dependent ATPase from cardiac muscle]. 13 43

In order to determine if there is a relationship between Na+, K+-ATPase inhibition and cardiac glycoside-induced arrhythmia, the time course of the onset and offset of the arrhythmia induced by the semi-synthetic glycoside, actodigin, and the enzyme activity during arrhythmia and following reversion to normal sinus rhythm was studied in the intact, anethetized dog. An infusion of actodigin(AY22,241) at the rate of 0.1 micronmol/kg/min for 30 min induced a severe and persistent arrhythmia within 13.1 +/- 192 min of 9 dogs. Upon termination of the actodigin infusion, the arrhythmia spontaneously converted to sinus rhythm within 17.5 +/- 2.3 min. Left ventricular tissue was taken from dogs sacrificed at the peak of the actodigin-induced arrhythmic periods or from the dogs that were allowed to recover from the actodigin-induced arrhythmia. These samples were homogenized and the membrane-containing fraction was passed through a Millipore filter. The membrane fraction trapped in the filter was then assayed for Na+ + K+ stimulated, Mg2+ dependent ATPase acctivity. The results showed that, in comparison to the time matched control dogs, the cardiac microsomes prepared from the arrhythmic dogs had a markedly reduced Na+, K+-ATPase activity. On the other hand, actodigin-treated dogs that were allowed to recover from the arrhythmic episode had Na+, K+-ATPase activity that was not significantly different from the control values. The amount of 3H-actodigin bound by the cardiac muscle microsomal fraction was also investigated. The microsomes from left ventricle were isolated with a slight modification of the method of Dutta et al. (1968). The microsomal binding of 3H-actodigin was maximum at 30 min (26.6 mol/mg protein) when the sample was prepared from the dogs at the peak of the arrhythmic effect. However, the binding was significantly reduced (11.5pmol/mg protein) in the microsomal fraction from hearts that had returned to sinus rhythm. These data provide direct evidence that inhibition of Na+, K+-ATPase and cardiac glycosideinduced arrhythmia may have some cause and effect relationship.
 ...
PMID:The relationship between Na+, K+-ATPase inhibition and cardiac glycoside-induced arrhythmia in dogs. 14 Mar 24

Calcium ions were shown to be actively accumulated in mitochondrial and microsomal fractions of uterine smooth muscle of rabbit and cattle. In presence of magnesium ions Ca2+ (10-6-10-4 M) activate microsomal ATPase from cattle uterus. The rate of formation and dissociation of the intermediate phosphorylated substance of Mg2+, Ca2+-ATPase was found to be lower in microsomes of smooth muscles than in sarcoplasmic reticulum of sceletal muscles. Serotonine (concentration 10-6 M) increased the dissociation of the intermediate phosphorylated substance from microsomes of uterine smooth muscle and decreased their capacity to bind Ca2+. At the same concentration serotonine inhibited the ATP-dependent accumulation of 45Ca by microsomes of uterine smooth muscle.
 ...
PMID:[Study of the active calcium transport mechanisms in uterine smooth muscle]. 14 May 26

The possibility that augmentation of cardiac Na+-K+-dependent adenosine triphosphatase (Na-K-ATPase) by L-3,5,3'-triiodothyronine (T3) was mediated by early changes in intracellular ion concentrations ([Na+]1, [K+]1) was explored by time-course analysis after a single injection of T3 in thyroid-ablated (131I) rats. At 6 and 16 h after injection, T3 had no significant effect on cardiac [Na+]1, [K+]1, or microsomal Na-K-ATPase activity. At 24 and 48 h, however, T3 elicited proportionate increases in [K+]1 and Na-K-ATPase activity. Thus, no evidence was adduced that the T3-dependent increase in ventricular Na-K-ATPase activity is an adaptive response to prior changes in intracellular ion concentrations. The increase in [K+]1 is attributable to an increase in Na+ pump activity. Administration of T3 to hypothyroid rats had no effect on the transition temperature or the activation energy of ventricular microsomal Na-K-ATPase, as analyzed by an Arrhenius plot. Thus, the lipid microenvironment and the properties of the enzyme may be independent of thyroid status. The latter inference was supported by kinetic analysis, in that T3 had no effect on the Km for ATP or the K1/2's for Na+ and K+. Injection of T3 of the hypothyroid rat, however, significantly increased the Vmax's for ATP, Na+, and K+ of ventricular microsomal Na-K-ATPase. These results are in accord with the inference of thyroidal induction of Na-K-ATPase indistinguishable from those present in the athyroid state.
 ...
PMID:Characteristics of thyroid-stimulated Na+-K+-ATPase of rat heart. 14 Jun 7


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>