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)

The surface distributions of three different membrane integral proteins, beta2-microglobulin (part of the histocompatibility antigen complex), aminopeptidase (alpha-aminoacyl-peptide hydrolase; EC 3.4.11.2), and the Na+,K+-ATPase (ATP phosphohydrolase; EC 3.6.1.3) on human fibroblasts grown in monolayer culture have been studied with their specific antibodies by immunofluorescence. On the same cells, the distribution of intracellular actin was observed by a spectrally distinct fluorescent staining procedure. If each of the antibody reagents was permitted to cluster its specific protein in the plane of the membrane, these clusters apparently became linked, through the membrane, to actin- and myosin-containing filaments (stress fibers) underneath the membrane, and were thereby immobilized. From these and other experiments, it appears that most, if not all, integral proteins can, upon clustering, form such transmembrane linkages to actin and myosin. A molecular mechanism for the formation of these linkages is proposed which postulates that actin is associated with the cytoplasmic surface of plasma membranes by peripheral attachment to a ubiquitous integral protein X in the membrane; when other integral proteins are induced to form clusters, they become bound to X and hence to actin (and myosin). The possible physiological role of these transmembrane linkages is briefly discussed.
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PMID:Antibody-induced linkages of plasma membrane proteins to intracellular actomyosin-containing filaments in cultured fibroblasts. 14

Mouse fibroblasts resistant to the drug rutamycin were isolated by selectively introducing BrdUrd into the mitochondrial genome of a line of mouse fibroblasts (clone 1 D) lacking a cytoplasmic thymidine kinase enzyme. The ATPase (ATP phosphohydrolase; EC 3.6.1.3) activity of mitochondria isolated from these cells was resistant to rutamycin. The rutamycin-resistant mutants were enucleated with cytochalasin B and fused with mouse A 9 cells resistant to 8-azaguanine and sensitive to rutamycin. Cytoplasmic hybrids, or cybrids, were selected as cells resistant to rutamycin and 8-azaguanine, and appeared at a high frequency. Other fusions between rutamycin-resistant nucleated cells and A 9 produced colonies at a much lower frequency. Finally, fusions between enucleated clone 1 D cells and A 9 cells produced no rutamycin-resistant colonies. These results indicate that rutamycin resistance is a cytoplasmically inherited characteristic in this cell line.
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PMID:Cytoplasmic inheritance of rutamycin resistance in mouse fibroblasts. 14 79

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

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 (Ca2+ + Mg2+)-dependent ATPase (ATP phosphohydrolase, EC 3.6.1.3) from human erythrocytes occurred in two different states, A-state and B-state, depending on the membrane preparation. The A-state showed low maximum activity (V) and the Ca2+ activation was characterized by a Hill coefficient, nH, of about 1 and a Michaelis constant, KCa, about 30 micron. The B-state showed high V, a nH above 1, which indicates positive cooperativity of Ca2+ activation, and KCa of about 1 micron. With varying ATP concentrations, both the A-state and B-state showed negative cooperativity and slightly different values of Km. The B-state was shifted to A-state when the membranes were exposed to low Ca2+ concentration. The shift reached 50% at approx. 0.5 micron Ca2+. At the low Ca2+ concentrations an activator was released from the membranes. The A-state was shifted to the B-state when the membranes were exposed to Ca2+ in the presence of the activator. The shift reached 50% at about 30 micron Ca2+. The recovery of high V was time dependent and lasted several minutes. Increasing concentrations of Ca2+ and activator accelerated the recovery. It is suggested that the A-state and the B-state correspond to enzyme free of activator and enzyme associated with activator, respectively. Furthermore, the two states may respresent a resting and an active state, respectively, of the calcium pump.
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PMID:Reversible shift between two states of Ca2+-ATPase in human erythrocytes mediated by Ca2+ and a membrane-bound activator. 14 93

The effect of the adenosine triphosphate analog, 6,6'-dithiobis(inosinyl imidodiphosphate), (sIMP-PNP)2, was tested on the ouabain-sensitive (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) and the ouabain-insensitive Mg2+ - ATPase in microsomes prepared from gill tissue of sea water-adapted rainbow trout, Salmo gairdneri. The (Na+ + K+)-ATPase was completely inhibited by low concentrations of (sIMP-PNP)2 (6 micrometer) but the Mg2+ - ATPase was unaffected by the inhibitor at concentrations as high as 28 micrometer, supporting the suggestion that the two activities represent separate enzymes. The specificity of inactivation could be demonstrated both at a physiological temperature (13 degrees C) and at 37 degrees C. The rates of inactivation were similar at both temperatures. Inactivation of the (Na+ + K+)-ATPase by (sIMP-PNP)2 was reversed by dithiothreitol, suggesting that the inhibitor forms a mixed disulfide with sulfhydryl groups on the enzyme. The inability of substrate (either ATP or its analog, adenyl-5'-yl imidodiphosphate) to protect against inactivation suggests that (sIMP-PNP)2 is reacting with sulfhydryl groups which are not associated with the active site.
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PMID:Inhibition of gill (Na+ + K+)-ATPase in rainbow trout (Salmo gairdneri) by a purinedisulfide analog of adenosine triphosphate. 14 62

Myosin has been isolated from bovine retinae and characterised by its ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity, its mobility in sodium dodecyl sulphate polyacrylamide gels and by electron microscopy. The purified myosin shows high ATPase activity in the presence of EDTA or Ca2+ and a low activity in the presence of Mg2+. The Mg2+-dependent ATPase activity is stimulated by rabbit skeletal muscle actin. The presumptive retinal myosin possesses a major component which has a mobility in sodium dodecyl sulphate polyacrylamide gel electrophoresis similar to that of the heavy chain of bovine skeletal muscle myosin. Electron microscopy showed retinal myosin to form bipolar filaments in 0.1 M KCl. It is concluded that the retina possesses a protein with enzymic and structural properties similar to those of muscle myosin.
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PMID:Purification and characterization of myosin from bovine retina. 14 64

The nerve growth factor protein (NGF) favors polymerization of brain actin and induces its organization to form paracrystalline structures that activate myosin ATPase (ATP phosphohydrolase, EC 3.6.1.3) to an extent greater than actin alone. Binding studies show that the initial 1:1 stoichiometry of NGF-G-actin complexes decreases to 1:7-10 when polymerization is ended and paracrystalline structures are formed. The ratio becomes even lower when heavy meromyosin is added in the absence of ATP, suggesting that heavy meromyosin displaces NGF bound to actin microfilaments. This conclusion is supported by the finding that when heavy meromyosin is added to NGF-microfilament complexes, under conditions for "decorating" microfilaments, the usual paracrystalline structure of the complexes disappears. The NGF-mediated organization of actin and activation of myosin ATPase is visualized as a self-regulatory and self-propagating mechanism, because progressive displacement of the growth factor induced by heavy meromyosin binding to F actin as ATP consumption proceeds renders an increasingly higher amount of NGF free for new interactions. These findings are discussed in the light of the mechanism of action of NGF in the target cells.
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PMID:Nerve growth factor potentiates actomyosin adenosinetriphosphatase. 14 85

The motility of demembranated sea urchin sperm flagella and that of embryo cilia reactivated with 0.1 mM ATP are completely inhibited by 4 micron and 0.5 micron vanadium(V) [V(V), in vanadate], respectively. The Mg2+-activated ATPase activity (ATP phosphohydrolase, EC 3.6.1.3)of the latent form of dynein 1 is inhibited 50% by 0.5-1 micron V(V), while the Ca2+-activated ATPase activity is much less sensitive. The inhibition of flagellar beat frequency and of dynein 1 ATPase activity by V(V) appears not to be competitive with ATP. In agreement with other reports, the inhibition of (Na,K)-ATPase by V(V) shows a slow onset in the presence of ATP and is relatively rapid in its absence. With dynein, however, the inhibition occurs at a rapid rate whether or not ATP is present. Catechol at a concentration of 1 mM reverses the V(V) inhibition of reactivated sperm motility, dynein ATPase, and (Na, K)-ATPase. Myosin and actomyosin ATPases show no inhibition by concentrations of V(V) up to 500 micron. The inhibition by V(V) provides a possible technique for distinguishing between the actions of dynein and myosin in different forms of cell motility.
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PMID:Potent inhibition of dynein adenosinetriphosphatase and of the motility of cilia and sperm flagella by vanadate. 14 86

The molecular architecture of membrane vesicles prepared from Escherichia coli ML 308-225 has been studied by using crossed immunoelectrophoresis, and a reference pattern of 52 discrete immunoprecipitates has been established. Progressive immunoadsorption experiments conducted with untreated control vesicles and with physically disrupted vesicles demonstrate that the membrane-associated immunogens fall into two categories: (i) those immunogens typified by ATPase (ATP phosphohydrolase, EC 3.6.1.3) and NADH dehydrogenase [NADH: (acceptor) oxidoreductase, EC 1.6.99.3] whose expression is minimal unless the vesicles are disrupted; and (ii) immunogens such as Braun's lipoprotein that are expressed to similar extents in untreated and in disrupted vesicles. A mathematical relationship between the peak area subtended by an immunoprecipitate in the crossed immuno-electrophoresis system and the quantity of vesicles used in the adsorption process has been derived. This relationship allows quantitation of the degree to which specific membrane immunogens partition between exposed and unexposed surfaces of the vesicle membrane. The results demonstrate conclusively that >95% of the membrane in the vesicle preparations is in the form of sealed sacculi with the same polarity as the intact cell. Moreover, the findings provide a strong indication that dislocation of immunogens from the inner to the outer surface of the membrane during vesicle preparation does not occur to an extent exceeding 11%.
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PMID:Molecular structure of membrane vesicles from Escherichia coli. 15 May 99


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