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)

An isolation procedure for synaptic plasma membranes from whole chick brain is reported that uses the combined flotation-sedimentation density gradient centrifugation procedure described by Jones and Matus (Jones, D. H. and Matus, A. I. (1974) Biochim. Biophys. Acta 356, 276-287) for rat brain. The particulate of the osmotically shocked and sonicated crude mitochondrial fraction was used for a flotation-sedimentation gradient step. Four fractions were recovered from the gradient after 30 min centrifugation. The fractions were identified and characterized by electron microscopy and by several markers for plasma membrane and other subcellular organelles. Fraction 2 was recovered from the 28.5-34% (w/v) sucrose interphase and contained the major part of the activities of the neuronal plasma membrane marker enzymes. The specific activities of the (Na+ +K+)-activated ATPase (EC 3.6.1.3), acetylcholinesterase (EC 3.1.1.7) and 5'-nucleotidase (EC 3.1.3.5) were, respectively, 4.5, 2.0 and 1.2 times higher than in the homogenate. However, Fraction 2 also contained considerable amounts of activities of putative lysosomal and microsomal markers in addition to lower amounts of mitochondrial and myelin markers. Although no prepurification of synaptosomes from the crude mitochondrial fraction was performed, the synaptic plasma membranes obtained showed many properties analogous to similar preparations from rat brain described in recent years.
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PMID:Isolation and partial characterization of chick brain synaptic plasma membranes. 13 94

We studied hearts from sham-operated and uninfected catheterized rabbits as well as from rabbits at early and late stages of cardiomyopathy and failure after 3 and 6 days of infection with Streptococcus viridans. No ultrastructural abnormalities or biochemical changes in membrane and myofibrillar activities were seen in 3-day uninfected hearts. In 6-day uninfected hearts there were decreased sarcolemmal M2+ ATPase, Na+-K+ ATPase, adenylate cyclase and calcium binding, microsomal calcium binding and uptake, and myofibrillar Ca2+-stimulated ATPase as well as increased mitochondrial calcium uptake. Slight ultrastructural changes also were apparent in 6-day uninfected hearts. At both early and late stages of infective cardiomyopathy and failure there were varying degrees of depression in sarcolemmal Mg2+ ATPase, Na+-K+ ATPase, adenylate cyclase and calcium binding, microsomal calcium binding, calcium uptake and basal ATPase, and myofibrillar Ca2+-stimulated ATPase activities. However, sarcolemmal Ca2+ ATPase and myofibrillar Mg2+ ATPase activities were decreased only after 6 days of infection. Mitochondrial calcium binding and uptake were increased in early stages but decreased in late stages of disease. Furthermore in infected hearts there were defects in mitrochondrial respiration and phosphorylation. Generalized severe myocardial cell damage involving myofibrils, mitochondria, and the sarcotubular system was seen only in late stages of infection. The results demonstrate impairment of different membrane and contractile protein functions as well as ultrastructural abnormalities in bacterial cardiomyopathic hearts which were absent or of lesser magnitude in hearts with only hypertrophy. The findings reported here suggest to use that there is an association between heart failure and changes in function of cellular components during bacterial infective cardiomyopathy.
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PMID:Abnormalities in heart membranes and myofibrils during bacterial infective cardiomyopathy in the rabbit. 13 11

In order to define pharmacological actions of ouabain in the dog heart, ouabain uptake and subcellular distribution and its effect on NaK ATPase (MG2+ dependent, Na+-K+-activated adenosinetriphosphate phosphohydrolase, E.C. 3.6.1.3), have been investigated in 21 open-chest dogs. A continuous infusion of ouabain (0.036 mug/kg/min) after a loading dose (20 mug/kg) produced a relatively constant plasma concentration of approximately 10(-8) M (6 ng/ml) ouabain, which induced a sustained positive inotropic response for the 300 min experimental period. In these hearts much greater binding of ouabain was noted in the NaK ATPase and microsomal fractions than in other myocardial fractions. No statistically significant inhibition of NaK ATPase activity was noted. Doubling the loading and infusion doses of ouabain raised the plasma level of ouabain to approximately 3 X 10(-8) M and produced various types of arrhythmia within an hour, which persisted for the rest of the 5 h experimental period. Under this experimental protocol there was a significant inhibition of NaK ATPase activity and increased binding of ouabain to this enzyme. This study does not support the hypothesis that there is a causal relationship between inotropic response to ouabain and NaK ATPase inhibition. It was concluded that NaK ATPase inhibition might be causally related to the development of ouabain toxicity.
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PMID:Cardiac NaK ATPase activity during positive inotropic and toxic actions of ouabain. 13 54

Sodium- and potassium-activated adenosine triphosphatase (NaK-ATPase) was purified from nasal salt glands of the duck (Anas platyrhynchos). Enzyme of specific activity 2,000 to 2,300 mumol of Pi/mg/hour was routinely obtained by sodium dodecyl sulfate treatment of a microsomal fraction of gland homogenate in the presence of 3 mM ATP followed by pelleting of the enzyme through a sucrose density gradient. Purified NaK-ATPase was stable for over 3 months at -20 degree. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography purified NaK-ATPase was shown to contain two polypeptide chains of molecular weight 94,000 and 60,000, the smaller of which was a glycoprotein. Purified enzyme of activity 2,300 mumol of Pi/mg/hour bound 3,600 pmol of ouabain/mg of enzyme protein. Reaction with [gamma-32P]ATP in the presence of Mg2+ and Na+ gave 7,025 pmol of acyl phosphate/mg of enzyme protein. The turnover number calculated from phosphorylation data was 5,460 min-1. Amino acid analysis of the polypeptide components of duck salt gland enzyme after separation by gel filtration chromatography in sodium dodecyl sulfate demonstrated strong compositional homology with highly purified NaK-ATPase preparations from other organs and species. The NH2-terminal amino acid of the 94,000-dalton component was glycine and of the 60,000-dalton component, alanine. With a combination of manual sequencing and automated Edman degradation, the NH2-terminal amino acid sequence of the 94,00-dalton catalytic subunit was found to be Gly-Arg-Asn-Lys-Tyr-Glu-Thr-Thr-Ala-()-Ser-Glu.
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PMID:Sodium- and potassium-activated adenosine triphosphatase of the nasal salt gland of the duck (Anas platyrhynchos). Purification, characterization, and NH2-terminal amino acid sequence of the phosphorylating polypeptide. 13 47

1 The effects of acebutolol, practolol and propranolol (0,5-3 mM) on calcium uptake, calcium binding and ATPase activities of the rabbit and rat heart microsomal and mitochondrial fractions were investigated. 2 Dose-response and time course experiments revealed that propranolol greatly inhibited microsomal and mitochondrial calcium uptake whereas both acebutolol and practolol showed slight depressant effects. 3 The ATPase activities of microsomal and mitochondrial fractions were decreased by acebutolol, practolol and propranolol; however, the latter agent was more effective than the other two. 4 The inhibitory effects of acebutolol, practolol and propranolol on mitochondria and microsomes were not antagonized by adrenaline. 5 Propranolol decreased calcium binding by the microsomal fraction only, whereas acebutolol and practolol had no effect on microsomal or mitochondrial calcium binding. 6 The sensitivity of the rabbit heart subcellular fractions to the beta-adrenoceptor blocking drugs was similar to that of the rat heart; however, the calcium uptake and ATPase activities of microsomes were more sensitive to propranolol than mitochondria in both species. 7 Perfusion of rat hearts with 0.2-1 mM propranolol decreased contractile force, and microsomal and mitochondrial fractions obtained from these hearts accummulated less calcium in comparison to the control. On the other hand, acebutolol and practolol (0.2-1nM) had no appreciable effects on contractile force or subcellular fractions under similar conditions. 8 The negative inotropic effect of propranolol may partly be due to its inhibitory actions on calcium transport by subcellular organelles of the myocardium; the depressant action of propranolol on calcium transport is unlikely to be due to its beta-adrenoceptor blocking property.
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PMID:Comparison of the actions of acebutolol, practolol and propranolol on calcium transport by heart microsomes and mitochondria. 13 77

Experiments were undertaken to substantiate the hypothesis that the mechanism of the direct effect of ouabain on the renal excretion of electrolytes is the result of inhibition of the transport enzyme, (Na, K)-ATPase. In dogs hydrated with saline, an injection of 3H-ouabain into the unilateral renal artery produced a continuing marked increase in excretion of water and sodium from the kidney, but not from the counter kidney. At maximal diuresis--90 min after ouabain injection, both kidneys were removed to assay microsomal ATPase activity and determine radioactivity distributed in subcellular structures. It was demonstrated that 3H-ouabain was deposited in the microsome fraction obtained from the injected kidney in concentrations ranging from 10(-7) to 10(-6) M/kg wet weight, and (Na, K)-ATPase activity of this fraction was inhibited as compared with that of the microsomal fraction obtained from control kidneys. Since (Na, K)-ATPase activity of renal microsomes was significantly inhibited in vitro by more than 10(-7) M of ouabain, ouabain concentration in microsomes obtained from the injected kidney was considered to be sufficient to inhibit ATPase activity. These findings indicate that ouabain diuresis under the present condition is closely related to direct inhibitory effect of ouabain on (Na, K)-ATPase activity of microsomes in tubular cells.
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PMID:Intrarenal distribution and ATPase inhibiting activity of ouabain in dogs. 13 62

Crude subcellular fractions from rat uterus contain a HCO-3 -stimulated Mg2+ -ATPase with properties analogous to those previously reported for the enzyme in gastric mucosa, pancreas, salivary gland and liver lyosome. Estradiol-17 beta treatment of ovariectomized rats resulted in an increase in uterine mitochondrial (HCO-3 +Mg2+)-ATPase and Mg2+ -ATPase activity. In an early response (105 min) to estradiol-17 beta treatment of ovariectomized rats, the lysosomal enzyme, beta-N-acetylglucosaminidase increased in the nuclear and mitochondrial fractions and decreased in the microsomal and supernatant fractions.
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PMID:Properties of a bicarbonate-stimulated ATPase from rat uterus. 13 20

Developmental changes in Ca2-+ ATPase activity were determined in submandibular glands of the rat from the fetus to the 300-day-old rat. Ca2+-ATPase in the homogenate fraction showed a rapid increase from the fetus to the 5-day-old rat, and from the 20- to 30-day-old rat. In the microsomal fraction, enzyme activity increased from the fetus to the 10-day-old rat, and after that is remained at almost the same level. Oscillatory phenomena of Ca2+-ATPase were observed in zymogen and mitochondrial fractions.
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PMID:Developmental changes of calcium-stimulated adenosine triphosphatase in rat submandibular gland. 13 8

The Mg-ATPase and (Na+ + K+)-stimulated Mg-ATPase in the mitochondrial and microsomal fraction of smooth muscular cells of the sheep's common carotid artery have been characterized in more detail. Optimal enzyme activities were found for all ATPases to be at pH 7.5-8.0 and 45 degrees C-50 degrees C. The energies of activation were found to be at 5-9 kcal/mole for both ATPases. Two-thirds of the (Na+ + K+)-stimulated Mg-ATPase were found to be ouabain-sensitive and thus attributed to the coupled (Na, K)-transport system. The pI 50 values of ouabain for microsomal and mitochondrial fractions are 6.3 and 6.0, respectively. The highest activity of (Na+ + K+)-stimulated Mg-ATPase is at 5-10 mM K+ and more than 50 mM Na+. One-third of the (Na+ + K+)-stimulated Mg-ATPase activity was found to be due to a stimulation of Mg-ATPase by Na+ alone, which is not inhibited by ouabain. The relationship of this activity to the ouabain-sensitive part of the (Na+ + K+)-stimulated Mg-ATPase and to Na+-transport is discussed. For the Mg-ATPases apparent KM(ATP) values were determined to be 1.4 and 1.0 mM, resp., and for the (Na+ + K+)-stimulated Mg-ATPases 0.15 and 0.14 mM, resp.
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PMID:Characterization of Mg-ATPase and (Na+ + K+)-stimulated Mg-ATPase in smooth muscular cells of the sheep's common carotid artery. 13 64

Skeletal muscles of flight rats showed no changes in the content of glycogen, adenosine triphosphatase activity of myosin and protein content in protein fractions (except the T fraction where the protein content increased on the 1st and returned to the normal on the 26th postflight day). On the 1st postflight day activities of aminotransferases and lactate dehydrogenase of sarcoplasmatic proteins were elevated and the isoenzyme spectrum of LDH was changed as if in muscular atrophy. The amount of free amino acids in muscles was lowered. On the 26 the postflight day the enzymic activity of sarcoplasmatic proteins remained increased whereas the isoenzyme spectrum of LDH returned to the normal and the amount of free amino acids grew significantly. In the microsomal fraction of muscles the phospholipid content decreased on the 1st and returned to the normal on the 26th postflight day.
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PMID:[Effect of a 22-day space flight on the metabolism of rat skeletal muscle tissue]. 13 80


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