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

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Insulin stimulates the activity of membrane-bound ATPase isolated from frog skeletal muscle and from rat brain. The increase in activity of the membrane-bound ATPase system isolated from frog ranged from 9-8 to 53% at concentrations of Na+ (25 mM), K+ (10 mM), and ATP (2 mM) similar to those in in vivo experiments conducted previously (Moore, 1973). The increased activity of the membrane-bound ATPase is, therefore, at least as great as the insulin-induced increase in Na efflux (10-38%) from intact cells (Moore, 1973). If the concentration of Na+ is lowered to 4 mM and that of ATP lowered to 0-5 mM albumin, and 10(6) M, the increase in ouabain-inhibitable ATPase activity can reach as high as 400%. 2. Ouabain, at a concentration (10(-3) M) sufficient to inhibit stimulation of the frog ATPase by increasing Na from 4 to 25 mM, completely blocked the stimulation of ATPase activity due to insulin. 3. At 2 mM-ATP, 100 mM-Na+, and 20 mM-K+, conditions which maximally activate the (Na+ + K+)-ATPase, insulin did not increase the ATPase, activity. Stimulation was consistently seen at 10 mM-K+, 0-5 mM-ATP, and either 4 mM or 25 mM-Na+. 4. The finding that insulin does not stimulate the ATPase activity in conditions in which the (Na+ + K+)-ATPase component is maximally activated and especially the fact that ouabain can reproducibly inhibit insulin stimulation of the membrane-bound ATPase activity strongly suggest that interaction of insulin with its receptor upon the plasma membrane somehow stimulates the (Na+ + K+)-ATPase system (ouabain sensitive; ATP phosphohydrolase, EC (3.6.1.3). These results are consistent with previous studies of the effect of insulin upon Na efflux from intact cells (Moore, 1973) and support the previous conclusion that the component of Na efflux stimulated by insulin is active. The evidence suggests that insulin probably does not affect Vmax of the (Na+ + K+)-ATPase system, but may increase the affinity of the enzyme system to one or more effectors, most likely Na+, ATP, and perhaps K+. 5. Oxidized glutathione (2-7 X 10(-6) M), 10(-6) M, 10(-7) M, and 10(-8) M cyclic AMP did not affect the ATPase activity 10(-6)Malbumin, and . 6. The results are consistent with the view that the Na pump, (Na+ + K+)-ATPase, is intimately involved with the physiological action of insulin and may be transducer between the binding of insulin to its receptor on the plasma membrane and the cellular actions of insulin.
...
PMID:Effect of insulin upon membrane-bound (Na+ + K+)-ATPase extracted from frog skeletal muscle. 12 36

The effect of depersolone, of the oxygenation of the perfusing solution and of phenoxybenzamine pretreatment has been studied in the isolated rat liver intermittently perfused with a solution containing low molecular weight dextran at 4 degrees C. The use in liver preservation of Collins' C3-solution and of a special albumin-containing solution was tested. The behaviour of acid and alkaline phosphatase, esterase, lactate dehydrogenase and adenosine triphosphatase in the preserved liver was followed by means of histochemical methods allowing semi-quantitative evaluation. Pretreatment with phenoxybenzamine and perfusion by an albumin-containing solution reduced the lesion of the liver, while prednisolone and oxygenation of the perfusion solution improved preserving effect only moderately.
...
PMID:Enzyme histochemical studies of the preserved rat liver. 14 May 69

The purification of a substance which protects mitochondrial activity against its decay in association with various cerebral pathologies, and the effect of this substance in vitro and in vivo have been mentioned. Defatted egg albumin was hydrolyzed with pronase, and diafiltrated through mesh, to obtain fractions of molecular weight less than 5,000. The diafiltrate was further fractionated using Sephadex G-25 column chromatography, and a fraction which had a protective action against the decay of mitochondrial DNP-ATPase activity was gathered. This digested egg albumin (DEA 5,000 S) showed no immunological reaction and seemingly penetrated well through the cell membrane. DEA 5,000 S prevented the decay of DNP-ATPase activity and swelling of brain mitochondria during aging in vitro. Also, the administration of DEA 5,000 S in vivo shortened the duration of unconsciousness and reduced EEG abnormalities in rats subjected to hypoxia in a special chamber filled with N2 gas. It is suggested that this Digested Egg Albumin has a marked action in restoring the function of metabolically impaired brain.
...
PMID:The pharmacological action of pronase-digested egg albumin upon cerebral hypoxia. 14 70

The isolated nuclei of wheat embryo possess the ATPase activity. The addition of Mg2+ and Ca2+ significantly increases the activities of nuclear ATPases, whereas Hg2+, Cu2+ and Mn2+ inhibit the activity. The activating effect of Mg2+ is enhanced by an addition of Na and K ions. The activity of wheat embryo nuclear Mg-ATPase is higher than its Ca-ATPase activity; both ATPases also differ in their pH optima. Separation of total nuclear protein according to the solubility of its individual protein components in wheat and strong salt solutions, using the detergents, as well as ammonium sulfate precipitation and dialysis do not result in separation of Mg-activated and Ca-activated ATPases, although their levels of activities and ratios change in the course of fractionation. The Mg- and Ca-ATPase activities of the wheat embryo nuclei were found in the nuclear fraction of albumin, in nonhistone proteins and nuclear membranes. In the albumin nuclear fraction and subfractions of non-histone proteins the higher level of activity is observed in Ca-ATPase, whereas in the nuclei and soluble fractions of residual proteins in Mg-ATPase.
...
PMID:[Properties and localization of Mg- and Ca-ATpase activities in wheat embryo cell nuclei]. 14 25

Long chain fatty acids were found to inhibit (Na+ + K+)-ATPase prepared from rat heart. Unsaturated and polyunsaturated fatty acids were more inhibitory than saturated fatty acids with myristic acid being the most inhibitory saturated fatty acid tested and linoleic the most inhibitory unsaturated fatty acid. As an example of fatty acid modification of the enzyme, inhibition of (Na+ + K+)-ATPase by oleate was examined. When compared to ouabain, inhibition of (Na+ + K+)-ATPase by oleate was found to be similar in that both were dependent on K+ concentration, but, in contrast to the almost instantaneous inhibition by ouabain, oleate inhibition was a slow process requiring over 20 min incubation at 37 degrees to produce maximum inhibition. Inhibition of rat heart (Na+ + K+)-ATPase by oleate was found to be readily reversible by washout. In the presence of albumin an oleate/albumin molar ratio greater than 7.5 was required for inhibition to occur. The activity of rat heart (Na+ + K+)-ATPase had a temperature optimum above 40 degrees and a discontinuous Arrhenius' plot with a transition temperature of 25 degrees. In the presence of oleate, however, the enzyme's optimum temperature decreased to below 40 degrees, the activation energy of the reaction at temperatures below 25 degrees was lowered from 24.7 kcal/mol to 12.6 kcal/mol and the enzyme had a linear Arrhenius' plot. The possibility of in vivo inhibition of cardiac (Na+ + K+)-ATPase under conditions of elevated fatty acids is discussed.
...
PMID:Long chain fatty acid inhibition of sodium plus potassium-activated adenosine triphosphatase from rat heart. 14 32

The effect of lipid peroxidation on the Ca2+-accumulating and Ca2+-retaining abilities of the microsomal fraction from chicken breast muscle was investigated. At 25 degrees C, enzymic lipid peroxidation did not seriously affect either of these abilities unless ascorbic acid was present, when both were diminished. At 37 degrees C, Ca2+-concentrating ability was decreased further by the effects of heat damage to the membrane. Membrane lipid peroxidation did not affect microsomal adenosine triphosphatase activity unless the microsomal fraction was subsequently washed with albumin. This effect of albumin is possibly due to removal of lipid-breakdown products. Addition of soya-bean phospholipids to the peroxidized vesicles washed with albumin restored adenosine triphosphatase activity, demonstrating a non-specific phospholipid requirement.
...
PMID:The effect of lipid peroxidation on the calcium-accumulating ability of the microsomal fraction isolated from chicken breast muscle. 15 35

1. The calcium-dependent ATPase activity of phospholipase-A2-digested sarcoplasmic vesicles decreases concomitantly with the contents of residual lysophospholipids and fatty acids when increasing albumin concentrations are applied. 2. Delipidated albumin preferentially removes unsaturated fatty acids and lysophosphatidylcholine. A complete removal of the phospholipids by albumin does not occur. 3. The membrane-bound lysophospholipids were analysed with respect to type of phospholipid, plasmalogen content and fatty acid chains by means of thin-layer chromatography and gas chromatography. 4. While the fatty acid composition of the lysophospholipids is independent of the degree of delipidation, the composition of the residual free fatty acids is found to change with the albumin concentration. 5. Reactivation of the Ca2+-ATPase by oleate leads to reasonable activities at room temperature as long as a minimum of about 30 lysophospholipid molec-les per ATPase is left. The course of the residual Ca2+-ATPase activity with the degree of delipidation is related to the presence of unsaturated fatty acids. 6. No specific role of either sphingomyelin or the plasmalogens has been found.
...
PMID:Effects of phospholipase A2 and albumin on the calcium-dependent ATPase and the lipid composition of sarcoplasmic membranes. 15 39

1. Enzymes, proteins, glycoproteins and lipids of rodent bile were compared with those of a plasma-membrane subfraction originating from the hepatocyte bile-canalicular membrane. 2. Three bile-canalicular glycoprotein enzyme activities were detected in bile. Comparison of the pH optimum and immunoinhibition properties of membrane and bile 5'-nucleotidase activity indicated that they were the same enzyme. Correspondence between membrane and bile alkaline phosphodiesterases also suggested that they were the same enzymes. Activities of Mg2+-stimulated adenosine triphosphatase, a lipid-dependent intrinsic membrane protein, and galactosyltransferase, a Golgi membrane marker, were not detected in bile. 3. Rodent bile contained 15 polypeptide bands that differed radically from those of bile-canalicular membranes. Bands that may correspond in molecular weight to liver plasma-membrane glycoproteins were present at low staining intensities in bile. A major protein of apparent molecular weight 49 500 was present, and albumin was detected by immunodiffusion. 4. The lipid composition of bile and bile-canalicular membrane also differed. Phosphatidylcholine accounted for 82% of rat bile phospholipids, and only trace amounts of phosphatidylinositol, phosphatidylserine and sphingomyelin were present. 5. The results indicate that in healthy animals, the bile-canalicular membrane is refractory to the action of bile acids during the secretory process. The presence of only small amounts of bile-canalicular membrane components, especially glycoprotein enzymes located at the outer face of the membrane, suggests that these are released from the membrane by bile acids after secretion of bile into the canalicular spaces.
...
PMID:Role of membranes in bile formation. Comparison of the composition of bile and a liver bile-canalicular plasma-membrane subfraction. 18 22

The transverse distribution of enzyme proteins and phospholipids within microsomal membranes was studied by analyzing membrane composition after treatment with proteases and phospholipases. Upon trypsin treatment of closed microsomal vesicles, NADH- and NADPH-cytochrome c reductases as well as cytochrome b5 were solubilized or inactivated, while cytochrome P-450 was partially inactivated. When microsomes were exposed to a concentration of deoxycholate which makes them permeable to macromolecules but does not disrupt the membrane, the detergent alone was sufficient to release four enzymes: nucleoside diphosphatase, esterase, beta-glucuronidase, and a portion of the DT-diaphorase. Introduction of trypsin into the vesicle lumen inactivated glucose-6-phosphatase completely and cytochrome P-450 partially. The rest of this cytochrome, ATPase, AMPase, UDP-glucuronyltransferase, and the remaining 50% of DT-diaphorase activity were not affected by proteolysis from either side of the membrane. Phospholipase A treatment of intact microsomes in the presence of albumin hydrolyzed all of the phosphatidylethanolamine, phosphatidylserine, and 55% of the phosphatidylcholine. From this observation, it was concluded that these lipids are localized in the outer half of the bilayer of the microsomal membrane; Phosphatidylinositol, 45% of the phosphatidylcholine, and sphingomyelin are tentatively assigned to the inner half of this bilayer. It appears that the various enzyme proteins and phospholipids of the microsomal membrane display an asymmetric distribution in the transverse plane.
...
PMID:Enzyme and phospholipid asymmetry in liver microsomal membranes. 19 Feb 41

A rapid small-scale procedure was set up to obtain highly purified preparations of lysosomes and plasma membranes from the homogenate of cerebellar granule cells differentiated in culture. It consisted in a centrifugation of the postnuclear fraction P2, on a Percoll gradient with formation of an upper and lower band. The upper band, upon centrifugation on 1 M sucrose, produced a light band lying on the top, that constituted the plasma membrane preparation. The upper band constituted the lysosome preparation. The plasma membrane preparation exhibited a 6-fold relative specific activity increase of Na+, K(+)-ATPase and 5'-nucleotidase, with negligible contamination by other subcellular markers; the lysosomal preparation exhibited a 30-fold relative specific activity increase of beta-galactosidase and beta-hexosaminidase, with virtually no contamination by other subcellular markers. Both the lysosome and plasma membrane preparations carried sialidase activity on MUB-NeuNAc and ganglioside GD1a. The sialidase activity on GD1a required the presence of Triton X-100 in both subcellular preparations; the sialidase activity on MUB-NeuNAc was markedly activated by albumin only in the lysosomes. The lysosomal sialidase had a unique optimal pH value, 3.9. The plasma membrane sialidase featured two values of optimal pH, one at 3.9, for both substrates and second at 5.4 and 6.0 for MUB-NeuNAc and GD1a, respectively. It is concluded that cerebellar granule cells differentiated in vitro possess one lysosomal sialidase and two plasma membrane sialidases, all of them active on ganglioside.
...
PMID:Dual subcellular localization of sialidase in cultured granule cells differentiated in culture. 130 62


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

---