Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The catecholamine transporter from bovine chromaffin granules has been solubilized by using low concentrations of sodium cholate in the presence of phospholipids. The functional solubilized protein has been incorporated into liposomes after removal of the detergent either by gel filtration or by dialysis. Reserpine-sensitive accumulation against a concentration gradient is achieved by artifically imposing a pH gradient across the membrane. In the reconstituted system adenosine 5'-triphosphate (ATP) serves as an energy source only at higher detergent concentrations. The proton-translocating adenosine triphosphatase (ATPase) is solubilized in parallel with the increasing efficiency of ATP as an energy source. Several criteria are proposed to distinguish between carrier-mediated (reserpine sensitive) and unmediated transport in the reconstituted system. The reserpine-sensitive process shows affinity and ss presented in this communication provide further support for the contention that concentrative uptake in biogenic amine storage vesicles is driven by a transmembrane pH gradient, which, in the native system, is generated by a proton-translocating ATPase. Moreover, the assays described provide a tool for the isolation and purification of the transport protein.
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PMID:Solubilization and reconstitution of the catecholamine transporter from bovine chromaffin granules. 4 69

Membrane vesicles were prepared by osmotic lysis of spheroplasts from M13-infected Escherichia coli. Reduced nicotinamide adenine dinucleotide (NADH) oxidase (reduced NAD: oxidoreductase, EC 1.6.99.3) and Mg2+-Ca2+-activated adenosine triphosphatase (ATP phosphohydrolase, EC 3.6.1.3), which are normally localized to the inner surface of the cytoplasmic membrane, were 50% acceesible to their polar substrates in these vesicles. The major coat protein of coliphage M13 is also bound to the cytoplasmic membrane (prior to phage assembly) but with its antigenic sites exposed to the exterior of the cell. Antibody to M13 coat protein was used to fractionate membrane vesicles. Neither agglutinated nor unagglutinated vesicles had altered NADH oxidase and adenosine triphosphatase specific activities. This is inconsistent with such vesicles being a mixture of correctly oriented and completely inverted membrane sacs and suggests that NADH oxidase, adenosine triphosphatase, M13 coat protein, or all three proteins rearrange during vesicle preparation.
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PMID:Fractionation of membrane vesicles from coliphage M13-infected Escherichia coli. 13 27

Purified (Na+, K+)-activated adenosine triphosphatase ((Na+, K+)-ATPase, ATP phosphohydrolase, EC 3.6.1.3) has been subjected to trypsin and chymotrypsin hydrolysis. The glycoprotein is much more resistant to proteolysis than the large chain. This differential susceptibility to proteolysis is not due to differences in the number of trypsin or chymotrypsin sensitive bonds because the two subunits are equally susceptible to proteolysis after isolation by preparative gel electrophoresis in sodium dodecyl sulfate. It is also not due to steric "shielding" of the glycoprotein by the large chain or its proteolytic products: (1) The rate of digestion of the glycoprotein is not increased after 90% of the large chain is digested. (2) The majority of the large chain peptides are released into the supernatant upon degradation. It is concluded that the greater resistance of the glycoprotein to proteolysis is due to its native conformation. In the absence of the large chain, the susceptibility of the glycoprotein to tryptic degradation by K+ and Na+. The evidence suggests that this decreased susceptibility was due to conformational changes in the glycoprotein. These specific ligand effects on proteolysis of the glycoprotein suggests that the glycoprotein may participate in Na+ and K+ binding by (Na+, K+)-ATPase.
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PMID:The susceptibility of the glycoprotein from the purified (Na+, K+)-activated adenosine triphosphatase to tryptic and chymotryptic degradation with and without Na+ and K+. 13 66

A protein fraction from the cellular slime mold Dictyostelium discoideum confers Ca2+-sensitivity on the activation of purified myosin adenosinetriphosphatase (ATP phosphohydrolase, EC 3.6.1.3) from Dictyostelium by purified Dictyostelium actin. That is, the fraction inhibits the actomyosin adenosine triphosphatase activity in the absence of Ca+ but not in the presence of Ca2+. This Ca2+-sensitizing factor affects only the actin-activated myosin adenosine triphosphatase and not the enzyme activity of myosin alone. The Ca2+-sensitivity is conserved when muscle actin replaces Dictyostelium actin, but is lost when muscle myosin replaces Dictyostelium myosin. The factor appears to be a protein since it is nondialyzable, is heat labile, and can be precipitated with ammonium sulfate. The factor can be purified 70-fold on an actin-affinity column.
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PMID:Calcium control of actin-activated myosin adenosine triphosphatase from Dictyostelium discoideum. 13 52

Actin can be cleaved by trypsin or chymotrypsin into a large, autonomous fragment with approximately 80% of the mass of the undegraded polypeptide. The protease-resistant cores obtained with either enzyme are very similar. Although the fragment does not bind calcium ions and fails to polymerize to the filamentous form of actin or to stimulate myosin adenosine triphosphatase (ATP phosphohydrolase, EC 3.6.1.3) activity, it retains the full capacity to bind ATP. This observation suggests that it represents an independent functional unit. Cleavage of globular actin with either trypsin or chymotrypsin occurs with half-times of 3 min, while that of filamentous actin proceeds with reaction half-times of 20 min for trypsin and nearly 2 hr for chymotrypsin. Denaturation and renaturation of the trypsin-resistant core shows that approximately 20% of the molecules refold to functional forms which indicates that the fragment can be considered as an independent unit of folding as well.
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PMID:ATP binding to a protease-resistant core of actin. 13 74

The purpose of this study was to investigate the contribution of mitochondrial and cytoplasmic protein synthesis to the biogenesis of cytochrome oxidase (ferrocytochrome c:oxygen oxidoreductase EC 1.9.3.1) and rutamycin-sensitive adenosine triphosphatase (ATP phosphohydrolase EC 3.6.1.3) in cultured oocytes of the toad, Xenopus laevis. X. laevis cytochrome oxidase was purified over 23-fold with respect to specific activity and over 29-fold with respect to specific heme a content from oocyte submitochondrial particles. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate separated the enzyme into six subunits with molecular weights of 44,000, 33,000, 23,000, 17,000, 12,000 and 9,500. the synthesis of the three larger subunits is sensitive to chloramphenicol (an inhibitor of mitochondrial protein synthesis), indicating that these subunits are made on mitochondrial ribosomes; the synthesis of the three smaller subunits is sensitive to cycloheximide (an inhibitor of cytoplasmic protein synthesis) and therefore occurs on cytoplasmic ribosomes. X. laevis rutamycin-sensitive ATPase, purified over 19-fold from oocyte submitochondrial pparticles, consists of 10 subunits with molecular weights of 56,000, 53,000, 41,000, 32,000, 29,000, 24,000, 21,000, 17,500 (2), and 11,500 on sodium dodecyl sulfate-polyacrylamide gels. The 29,000, 21,000, and one of the 17,500-dalton polypeptides are synthesized in the presence of cycloheximide and are, therefore, products of mitochondrial protein synthesis; the synthesis of the remaining seven subunits occurs in the presence of chloramphenicol, indicating that these subunits are made on cytoplasmic ribosomes. The synthesis of protein by mitochondria in cultured oocytes appears to be dependent upon cytoplasmic protein synthesis. In the presence of cycloheximide, the mitoribosomal synthesis of the subunits of cytochrome oxidase and rutamycin-sensitive ATPase is detectable only after a prior inhibition of mitochondrial protein synthesis by chloramphenicol. Oocyte mitochondrial ribosomes synthesize at least nine polypeptides after chloramphenicol treatment, three of which are components of neither cytochrome oxidase nor rutamycin-sensitive ATPase.
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PMID:Synthesis of the mitochondrial inner membrane in cultured Xenopus laevis oocytes. 18 93

The effects of ouabain, Rb+ and Tl+ on Na+, K+-adenosine triphosphatase (Na+,K+-ATPase; Mg++-dependent, Na+,K+-activated ATP phosphohydrolase, EC 3.6.1.3) and contractile force were compared in guinea-pig and rat hearts. Although ouabain produced a dose-dependent positive inotropic effect in rat as well as in guinea-pig atrial preparations, concentrations of ouabain needed to produce comparable positive inotropic effects were more than an order of magnitude higher in rats than in guinea pigs. Additionally, the time to reach the plateau of the inotropic response was significantly shorter in rat than in guinea-pig atrial preparations. Concentrations of ouabain needed to produce comparable inhibition of cardiac Na+, K+-ATPase in vitro observed with partially purified cardiac enzyme preparations were also more than an order to magnitude higher in rats than in guinea pigs.
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PMID:Comparative species studies on the effect of monovalent cations and ouabain on cardiac Na+, K+-adenosine triphosphatase and contractile force. 127 Dec 88

The proton-translocating adenosine triphosphatase (ATPase) of bovine chromaffin granules contains up to five different polypeptides. Its activity is inhibited by N-ethylmaleimide, and ATP protects the enzyme from inhibition. After treatment of membranes with N-[2-3H]ethylmaleimide, only one polypeptide is strongly radiolabelled: this is the largest (70 kDa) subunit of the proton-translocating ATPase. This subunit therefore contains the ATP-hydrolysing site. Two-dimensional electrophoresis reveals heterogeneity in this polypeptide.
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PMID:Proton-translocating adenosine triphosphatase of chromaffin-granule membranes. The active site is in the largest (70 kDa) subunit. 287 37

An antiserum was prepared against a highly purified Na(+), K(+)-adenosine triphosphatase (ATP phosphohydrolase, EC 3.6.1.3). Purification and fractionation yielded two globulin components, one of which appears specific for a digitalis glycoside receptor site or binding conformation and the other for a catalytic site or conformation.
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PMID:Effects of an antibody to a highly purified Na+, K+-ATPase from canine renal medulla: separation of the "holoenzyme antibody" into catalytic and cardiac glycoside receptor-specific components. 427 66

The presence of adenosine triphosphate, guanosine triphosphate, cytosine triphosphate, or uridine triphosphate reduced the rate of inactivation of vaccinia when heated at 50 C. The virus-associated nucleoside triphosphate phosphohydrolases (adenosine triphosphatase, guanosine triphosphatase, cytosine triphosphatase, and uridine triphosphatase) and ribonucleic acid polymerase were also protected from heat inactivation by these compounds. These obervations are best explained by postulating that ribonucleoside triphosphates bind to enzymes in the virus particle, and that these enzyme-substrate complexes are more resistant to thermal denaturation than are the enzymes without their substrates. The kinetics of heat inactivation of the vaccinia ATP phosphohydrolase activity is biphasic, suggesting that there are two proteins in the vaccinia particle that have this enzyme activity but they have different kinetics of heat inactivation. Any of the vaccinia-associated nucleotide phosphohydrolase activities are protected from heat inactivation by the presence of any one of the respective nucleoside triphosphates. This observation suggests that there is a single enzymatic site in vaccinia that is able to react with any ribonucleoside triphosphate.
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PMID:Protection of vaccinia from heat inactivation by nucleotide triphosphates. 431 59


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