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)

Genetically obese (ob/ob) mice, mice that became obese after treatment with gold thioglucose, and lean animals were studied in the euthyroid state, after induction of hypothyroidism, and after treatment with triiodothyronine. The activity of glycerol 3-phosphate dehydrogenase (sn-glycerol-3-phosphate:(acceptor) oxidoreductase; EC 1.1.99.5] was reduced in the livers from hypothyroid animals and was increased by treatment with triiodothyronine in all groups. The activity of the ouabain-suppressible sodium- and potassium-dependent ATPase (ATP phosphohydrolase; EC 3.6.1.3) was increased by triiodothyronine and reduced by hypothyroidism in the lean and gold thioglucose-treated obese animals. In the obese (ob/ob) mice, on the other hand, treatment with triiodothyronine did not increase the activity of this enzyme, which remained at the level found in hypothyroid animals. This enzymatic activity was reduced in both liver and kidney. Adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); EC 4.6.1.1] activity in liver membranes, however, was similar in all three groups of mice. This enzyme complex was activated by glucagon and was unaffected by treatment with thyroid hormones. The lack of a thyroid-dependent ouabain-suppressible (Na(+) + K(+))-ATPase in the tissues of the obese (ob/ob) mouse could explain most, if not all, of the abnormalities that have been described in this animal.
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PMID:An enzymatic defect in the obese (ob/ob) mouse: loss of thyroid-induced sodium- and potassium-dependent adenosinetriphosphatase. 14 80

A simple, rapid and reproducible method for the reversible removal of lipids from a membrane-bound enzyme is described. Essentially, a membrane preparation containing (Na+ + K+)-dependent adenosine triphosphatase was extracted with the non-ionic detergent Lubrol WX in the presence of glycerol, and partial separation of protein from lipid was achieved with the use of only two centrifugations. About 74% of the endogenous phospholipid and 79% of the cholesterol were removed, concomitant with a virtually complete loss of ouabain-sensitive adenosine triphosphatase activity, but with retention of 60-100% of the K+-dependent phosphatase activity. The addition of pure phosphatidylserine re-activated the enzyme to more than 80% of the initial activity, and up to 30% of the protein was recovered. Excess of phosphatidylserine could be washed off the enzyme to give a stable 'reconstituted' preparation. The effects of variation in the experimental conditions were examined, and the results are discussed with respect to the possibility of adapting the method to the study of other lipid-dependent enzymes bound to membranes.
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PMID:A simple and rapid method for the reversible removal of lipids from a membrane-bound enzyme. 14 78

Effects of commonly used purification procedures on the yield and specific activity of (Na+ + K+)-ATPase (Mg2+-dependent, Na+ + K+-activated ATP phosphohydrolase, EC 3.6.1.3), the turnover number of the enzyme, and the kinetic parameters for the ATP-dependent ouabain-enzyme interaction were compared in canine brain, heart and kidney. Kinetic parameters were estimated using a graphical analysis of non-steady state kinetics. The protein recovery and the degree of increase in specific activity of (Na+ + K+)-ATPase and the ratio between (Na+ + K+)-ATPase and Mg2+-ATPase activities during the successive treatments with deoxycholate, sodium iodide and glycerol were dependent on the source of the enzyme. A method which yields highly active (Na+ + K+)-ATPase preparations from the cardiac tissue was not suitable for obtaining highly active enzyme preparations from other tissues. Apparent turnover numbers of the brain (Na+ + K+)-ATPase preparations were not significantly affected by the sodium iodide treatment, but markedly decreased by deoxycholate or glycerol treatments. Similar glycerol treatment, however, failed to affect the apparent turnover number of cardiac enzymes preparations. Cerebral and cardiac enzyme preparations obtained by deoxycholate, sodium iodide and glycerol treatments had lower affinity for ouabain than renal enzyme preparations, primarily due to higher dissociation rate constants for the ouabain.enzyme complex. This tissue-dependent difference in ouabain sensitivity seems to be an artifact of the purification procedure, since less purified cerebral or cardiac preparations had lower dissociation rate constants. Changes in apparent association rate constants were minimal during the purfication procedure. These results indicate that the presentyl used purification procedures may alter the properties of membrane (Na+ + K+)-ATPase and affect the interaction between cardiac glycosides and the enzyme. The effect of a given treatment depends on the source of the enzyme. For the in vitro studies involving purified (Na+ + K+)-ATPase preparations, the influence of the methods used to obtain the enzyme preparation should be carefully evaluated.
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PMID:Membrane (Na+ + K+)-ATPase of canine brain, heart and kidney. Tissue-dependent differences in kinetic properties and the influence of purification procedures. 14 5

The understanding of the effects of cannabinoids in human subjects has been obscured by a lack of knowledge about how the various active principles from marijuana act at the cellular level in the brain. For this reason the present study was undertaken to determine the effects of cannabinoids on the enzymes associated with the synaptic membranes. Electron micrographic analysis was performed to determine the purity of synaptic membrane preparations from rat brain, and subsequently such preparations were subjected to additions of ethanol, Tween-80, 80% glycerol, and either delta-tetrahydrocannabinol, 11-hydroxy-delta-tetrahydrocannabinol, or cannabinol. Both sodium and potassium activated ATPase (Na, K-ATPase), and Mg-ATPase were measured as the micrometer orthophosphate (P) released per minute per microgram membrane protein and these specific activities of the enzymes expressed as absolute values and as the percentage depression brought about by the cannabinoids. The ATPase spcific activities are taken from the rate curve over a 30-min incubation time. Additionally, synaptic membrane acetylcholineesterase specific activity was measured by continuous rate enzyme assay. While as low as 10 M delta-tetrahydrocannabinol showed appreciable decrements in both the membrane-bound ATPases, the other cannabinoids did not show such a great depression in enzyme activity. The specific activity of acetylcholinesterase, which is weakly bound to the membrane, showed only slight or no changes in activity with the various cannabinoids. It was additionally shown that the cannabinoids, delta-tetrahydrocannabinol in particular, bound to the synaptic membranes almost irreversibly in the in vitro system, and that the vehicle for dissolving the cannabinoids, while used as background control values when calculating the percentage decrements in enzyme specific activity, did vary the effects on the ATPase enzymes in particular. These data are discussed in relation to psychotomimetic activity of the cannabinoids.
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PMID:Effects of cannabinoids on synaptic membrane enzymes. I. In vitro studies on synaptic membranes isolated from rat brain. 14 40

We have previously reported on the isolation of a mutant strain of Escherichia coli, RF-7, that has a dicyclohexylcarbodiimide (DCCD)-resistant, membrane-associated adenosine triphosphatase (ATPase) activity (R. H. Fillingame, J. Bacteriol. 124:870--883, 1975). We report here that the DCCD resistance of the ATPase of this mutant varies significantly, depending upon the carbon source used for growth. When strain RF-7 was grown aerobically on either glycerol or glucose or anaerobically on glucose rather than on a combination of succinate, acetate, and malate, ATPase activity was more sensitive to inhibition by DCCD because the carbodiimide-reactive proteolipid reacted more readily with DCCD.
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PMID:Carbodiimide-resistant mutant of Escherichia coli: suppression of resistance to dicyclohexylcarbodiimide by growth on glucose or glycerol. 14 7

The mitochondrial F1-ATPase is irreversibly inactivated by the adenine nucleotide analogue, p-fluorosulfonylbenzoyl-5'-adenosine. This inactivation is partly prevented by the presence of bound adenine nucleotides. Inactivations of the ATPase with p-fluorosulfonyl[14C]benzoyl-5'-adenosine were most efficiently accomplished with the nucleotide-free enzyme at pH 7.0, in a buffer containing 20% glycerol. Under these conditions, 4.2 g atoms of 14C are incorporated per 350,000 g of enzyme when the ATPase is inactivated by 90% by its reaction with 2 mM p-fluorosulfonyl[14C]benzoyl-5'-adenosine. Isolation of the component polypeptide chains of the labeled ATPase showed that all of the radioactivity was associated with the two largest subunits. The isolated alpha subunit contained 0.45 g atom of 14C/mol and the isolated beta subunit contained 0.88 g atom of 14C/mol. Hence, the inactivation can be correlated with the incorporation of 14C into the beta subunit. This suggests that the hydrolytic site of the enzyme resides on this subunit. The majority of the radioactivity in a tryptic digest of labeled beta subunit is contained ina tryptic peptide that has the following amino acid sequence: Ile-Met-Asp-Pro-Asn-Ile-Val-Gly-Ser-Glu-His-Tyr-Asp-Val-Ala-Arg, where Tyr is the radioactive derivative of the tyrosine residue that was sulfonylated during the inactivation.
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PMID:Identification of a tyrosine residue at a nucleotide binding site in the beta subunit of the mitochondrial ATPase with p-fluorosulfonyl[14C]-benzoyl-5'-adenosine. 15 Apr 16

Cytochemical techniques have been employed to study the localization of adenylate cyclase and (Ca2+ + Mg2+)-stimulated ATPase activities in platelets after fixation. Biochemical analysis of adenylate cyclase demonstrated a 70% reduction in activity in homogenates from fixed cells, but the residual activity could be stimulated 10--20 times by prostaglandin E1 (1 micrometer) under the same incubation conditions as employed in the cytochemical studies (e.g. media containing 2 mM lead nitrate and 10 mM NaF). Adenylate cyclase activity employing 5'-adenylyl-imiodiphosphate (AMP-P(NH)P) as substrate was found to be associated with the dense tubular system (smooth endoplasmic reticulum) in intact fixed platelets, and was apparent only when the cells were incubated with prostaglandin E1. Less activity was found along the membranes of the surface connected open canalicular system and occasionally at the outer cell surface. Enzymatic activity was blocked by the adenylate cyclase inhibitor 9-(tetrahydro-2-furyl) adenine and was not due to AMP-P(NH)P phosphohydrolase activity. The low adenylate cyclase activity in the surface membranes may be due to enzyme inactivation as a result of fixation, since a surface membrane fraction obtained by the glycerol lysis technique from unfixed cells had an adenylate cyclase specific activity equivalent to that in the microsomal membrane fraction. (Ca2+ + Mg2+)-stimulated ATPase activity was found associated with the membranes of the surface connected open canalicular system in unfixed cells. After brief fixation (5--15 min) with glutaradehyde, strong (Ca2+ + Mg2+)ATPase activity became apparent in the dense tubular system. Longer periods of fixation inactivated enzymatic activity. Addition of Ca2+ (1.0 mM) to incubation medium with low Mg2+ (0.2 mM), or increasing Mg2+ to 4.0 mM, in both cases strongly stimulated enzyme activity. The ATPase activity in the platelet membranes was not inhibited by ouabain. It is suggested that the Ca2+-stimulated ATPase and adenylate cyclase activities in the dense tubules may possibly be involved in regulation of intracellular Ca2+ transport.
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PMID:Cytochemical localization of adenylate cyclase and of calcium ion, magnesium ion-activated ATPases in the dense tubular system of human blood platelets. 15 Aug 66

Glycerol-treated muscle fiber bundles were fixed at their rest length in 50 mM KC1, 2 mM MgC1(2), and 10 micron CaC1(2) at pH 7.8 and 0 degrees C in the presence of sufficient amounts of ATP, creatine kinase, and creatine phosphate. The fiber bundles were stretched linearly with time for 0.3 s at a constant amplitude, suddenly released, then fixed at the rest length for a constant time interval (alpha seconds). The stretch-release cycle was repeated, and the ATPase activity (the rate of ADP liberation) [EC 3.6.1.3] was measured. It was found that: 1. ATPase was activated by repeated stretch-release. As repetitive stretch-release of 1--2% of the rest length caused maximum activation, we usually selected a value of 2.5% of the rest length. The activation of ATPase was found to be a function of the duration, alpha, of the isometric phase after sudden release from stretching. The ATPase activity of fiber bundles was almost unaffected when they were oscillated by a simple stretch-release without an isometric phase after the sudden release (alpha=0). 2. The ATPase activity of oscillated muscle fibers increased with increase in the value of alpha, reached a maximal level, then decreased gradually with further increase of alpha to a value slightly larger than that of static fibers. At 0 degrees C, the value of alpha for the maximum activation was observed at about 2 s, and the maximum activity was about 2.5 times that of static fibers. At 20 degrees C, the alpha value for maximum activation was about 0.5 s, and the maximum activity was about 1.8 times that of static fibers. 3. The time course of ADP liberation after one stretch-release cycle could be easily calculated from the ATPase activity of the summed durations of the isometric phase, alpha, assuming that the ATPase activation was turned off and on by the stretching and release, respectively, and that the state of cross-bridges immediately after the stretch-release was independent of alpha of the cycle. The rate of ADP liberation after stretch-release thus obtained showed a short lag phase, a sigmoidal increase, a decrease to almost zero, then a return to nearly the original level (the rate of static fibers). About 1.3 mol of ATP per mol of myosin was hydrolyzed at both 0 degrees C and 20 degrees C during one cycle of the changes in the rate of ADP liberation.
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PMID:Acceleration of the ATPase activity of glycerol-treated muscle fibers by repeated stretch-release cycles. 15 10

A pure, enzymatically active Ca2+-dependent adenosine triphosphatase (Ca2+-ATPase) has been isolated from canine ventricular sarcoplasmic reticulum. In contrast to that derived from skeletal muscle, the Ca2+-ATPase from cardiac sarcoplasmic reticulum was more active when solubilization and subsequent purification took place in the presence of its substrates, Ca2+ and ATP. Cholate- or deoxycholate-solubilized Ca2+-ATPase is recovered following rapid glycerol dilution and centrifugation. The Ca2+-ATPase is stable and possesses hydrolytic capacities up to 4 mumol/mg/min. Sodium dodecyl sulfate-polyacrylamide gels reveal the presence of one protein in the range of 95,000 to 100,000 daltons. This method also yields purified Ca2+-ATPase from fast skeletal muscle of similar activities to those reported by other laboratories.
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PMID:Rapid purification of canine cardiac sarcoplasmic reticulum Ca2+-ATPase. 15 59

1. Soluble ATPase (adenosine triphosphatase) activity is released when rat liver submitochondrial particles are shaken with chloroform, provided that ATP or glycerol is present in the suspending medium. The extraction is very rapid and appears to be complete. 2. The ATPase of the chloroform extract is about 50% pure and can be readily purified to a specific activity of 60-70mumol/min per mg of protein by (NH(4))(2)SO(4) fractionation and column chromatography on Sephadex G-200. 3. The particulate and soluble ATPases have many similar properties, including their K(m) values for ATP, activation by various metal ions, hydrolytic activity with other nucleotides and stimulation by bicarbonate ions. 4. Unlike the particulate enzyme, the soluble enzyme is cold-labile and insensitive to oligomycin. 5. The molecular weight indicated by the mobility of the soluble ATPase on Sepharose 6B is 360000. 6. The soluble ATPase combines very readily with liver submitochondrial particles depleted of ATPase by salt extraction, and oligomycin-sensitivity is restored. Very little recombination of the enzyme occurs with chloroform-extracted particles. 7. The soluble enzyme contains orcinol-reactive material, suggesting that it may be a glycoprotein. The carbohydrate content was estimated to be 1-2% by weight. 8. It is concluded that the liver ATPase obtained by the chloroform extraction method of Beechey, Hubbard, Linnett, Mitchell & Munn [(1975) Biochem. J.148, 533-537] is similar to other preparations described previously and that this method is superior in simplicity and speed.
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PMID:Purification and properties of the adenosine triphosphatase released from the liver mitochondrial membrane by chloroform. 15 21


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