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 effects of acute (10 mg/kg) and chronic 10 mg/kg for 30 days) administration of delta-9-tetrahydrocannabinol (delta9-THC) have been studied histochemically in the rat adrenal medulla, which include total catecholamines, noradrenaline, histometric measurements of adrenal medullary areas, calcium content of the medullary cells along with adenosine triphosphatase (ATPase), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) activities. Acute delta9-THC treatment reduced the total catecholamine content (including noradrenaline) of the gland, was accompanied by increased ATP-ase, AChE, BChE activities and increased calcium distribution in the gland. Chronic delta9-THC treatment caused significant hypertrophy of the chromaffin tissue, with decreased total catecholamine content, although noradrenaline containing areas exhibited no notable change. The calcium content and ATPase activity were increased along with a concomitant increase in AChE and BChE activities. Although the changes in adrenal medullary enzyme activities following both acute and chronic delta9-THC treatment are qualitatively similar, marked quantitative increase is noted in the chronically treated groups. The results indicate an increased total catecholamine releasing activity of the adrenal medulla following acute delta9-THC treatment, while chronic delta9-THC administration produces a preferential release of adrenaline.
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PMID:Changes in rat adrenal medulla following delta9-tetrahydrocannabinol treatment. A histochemical study. 12 28

The Ca2+-sensitive ATPase (adenosine triphosphatase) of human erythrocyte membranes is activated, not only by Ca2+ ions, but also by a series of other bivalent metal ions including Sr2+, Ba2+, Mn2+, Ni2+, Co2+, Cd2+, Cu2+, Zn2+ and Pb2+. The degree of activation is dependent on the radius of the ion rather than on its nature, in contrast with the dissociation constant of the enzyme--metal ion complex.
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PMID:Activation of membrane-bound high-affinity calcium ion-sensitive adenosine triphosphatase of human erythrocytes by bivalent metal ions. 12 84

1. The function of mitochondria, sarcotubular membranes (heavy microsomes), sarcolemma and myofibrils from the hind-leg skeletal muscle of about 60- and 150-day-old normal and myopathic (UM-X7.1) hamsters was examined. 2. The mitochondrial calcium uptake as well as mitochondrial phosphorylation and respiratory rates were lower in 60-day-old myopathic skeletal muscle, unlike 150-day-old myopathic animals, when pyruvate-malate and glutamate-malate were used as substrates. However, mitochondria from 150-day-old myopathic animals showed depressed glutamate-dependent respiratory and phosphorylation rates and succinate-supported initial rate of calcium uptake. 3. The microsomal calcium-uptake, but not calcium-binding, and Ca2+-stimulated adenosine triphosphatase (ATPase) activity of the 150-day-old myopathic skeletal muscle were lower than the control values. Although microsomal calcium-binding, calcium-uptake and ATPase activities of the 60-day-old myopathic muscle were not depressed significantly, the initial rate of calcium uptake was less than the control. 4. The sarcolemmal Ca2+-ATPase, but not Mg2+-ATPase or Na+ +K+-ATPase, activity was higher in 60-day-old myopathic muscle whereas the activities of all these enzymes from 150-day-old myopathic animals were higher than the control. On the other hand, the Na+ +K+-ATPase activities from 60- and 150-day-old myopathic animals were inhibited by ouabain to a lesser extent in comparison with the respective control values. 5. The myofibrillar Ca2+-ATPase and Mg2+-ATPase activities as well as inhibition of Mg2+-ATPase due to Na+ and K+ in myopathic muscle were no different from the control values. 6. The results reported here give further support to the view that different membrane systems of the dystrophic muscle are defective.
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PMID:Defective membrane systems in dystrophic skeletal muscle of the UM-X7.1 strain of genetically myopathic hamster. 12 86

In contrast with wild-type Salmonella typhimurium LT2, strain HfrA did not have ATP-driven energy-dependent transhydrogenase activity, although ATP-dependent quenching of atebrin fluorescence was normal. Respiration-dependent and energy-independent transhydrogenase, and Ca2+-activated ATPase (adenosine triphosphatase) activities were similar in both strains. Purified ATPases from the two strains had similar specific activities, similar subunit polypeptides, and were equally effective in restoring energy-dependent transhydrogenase activities to membrane particles of strain LT2 from which the ATPase had been stripped. The purified ATPases from both strains could restore respiration-dependent but not ATP-dependent transhydrogenation to stripped particles of strain HfrA. Both strains grew aerobically equally well on salts media containing glucose, malate, succinate, citrate, acetate, pyruvate, fumarate, lactate or aspartate as substrates. Growth on glucose under anaerobic conditions was similar. Strains LT2 and HfrA were equally effective in the accumulation under both aerobic and anaerobic conditions of the amino acids proline, phenylalanine, histidine, lysine, isoleucine and aspartic acid. Inhibition of amino acid accumulation by KCN and dicyclohexylcarbodi-imide occurred to the same extent in both strains. The complete inhibition by dicyclohexylcarbodi-imide of amino acid uptake under anaerobic conditions suggested that ATP could drive amino acid uptake in both strains. The ability of strain HfrA to carry out ATP-dependent transport or quenching of atebrin fluorescence but not ATP-dependent transhydrogenation is different from the wild-type strain and from any previously described energy-coupling mutant. It is difficult to reconcile the properties of this mutant with the chemiosmotic hypothesis.
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PMID:Salmonella typhimurium HfrA, a mutant in which adenosine triphosphate can drive amino acid transport but not energy-dependent nicotinamide nucleotide transhydrogenation. 12 57

The nature of the energy requirement for irreversible adsorption of phages T1 and phi80 was studied by using various specific energy inhibitors and mutants lacking either the Ca2+, Mg2+-adenosine triphosphatase or the ability to produce cytochromes in the absence of added 5-aminolaevulinic acid. It was found that irreversible adsorption could be energized both through the electron transport chain and from adenosine 5'-triphosphate via the Ca2+, Mg2+-adenosine triphosphatase, indicating the involvement of the energized membrane state. These results and the discovery that phages T1 and phi80 adsorb reversibly to the isolated tonA gene product are discussed in terms of the possible involvement of functions expressed by the tonB gene region in irreversible adsorption and the relationship to iron transport.
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PMID:Nature of the energy requirement for the irreversible adsorption of bacteriophages T1 and phi80 to Escherichia coli. 12 53

A mutant of Escherichia coli has been isolated that grows poorly on succinate and exhibits a markedly reduced sensitivity to colicin K. This mutant is also deficient in the respiration-linked transport of proline and thiomethyl-beta-D-galactoside but appears normal for the adenosine triphosphate-dependent transport of glutamine and arginine. A temperature-conditional revertant of the mutant grows on succinate and is sensitive to colicin K at 27 C, but fails to grow on succinate and is insensitive to colicin K at 42 C. Proline transport in the temperature-conditional revertant is reduced at 42 C when either glucose or succinate is used as energy source. Glutamine transport, on the other hand, is normal at 42 C with glucose as energy source, but is reduced with succinate, although not to the same extent as is proline transport. The lack of growth on succinate and the deficiencies in transport at 42 C are not due to a temperature-dependent lesion in either the electron transport chain or in Ca2+, Mg2+-activated adenosine triphosphatase activity. Membrane vesicles prepared from the temperature-conditional revertant are impaired in proline transport at both 27 and 42 C. These findings suggest the existence in the cytoplasmic membrane of E. coli cells of a component, presumably protein, that is required for colicin K action and that functions in respiration-linked and, to a lesser degree, in adenosine triphosphate-dependent active transport systems. This protein may serve as the primary target of colicin K action.
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PMID:Mutant of Escherichia coli defective in response to colicin K and in active transport. 12 54

Temporal patterns of biosynthesis of the Ca2+ + Mg2+-dependent adenosine triphosphatase of sarcomplasmic reticulum were obtained from studies with primary cultures of rat skeletal muscle cells. Rates of synthesis at various stages of differentiation were estimated from the incorporation of tritium-labeled leucine into the ATPase. Cells were solubilized with detergent, and newly synthesized ATPase was isolated from cells by antibody precipitation in the presence of carrier ATPase. Radioactivity incorporated into the ATPase was determined after gel electrophoresis of the precipitates and counting of gel slices containing the ATPase band. In Dulbecco's modified Eagle's medium containing 10% horse serum and 0.5% chick embryo extract, mononucleated myoblast cells began to form multinucleated myotubes after about 50 hours in culture. Prior to fusion little ATPase synthesis was detectable; during fusion the ATPase was synthesized at an accelerating rate for a period of about 30 hours. The rate of synthesis levelled off after about 90 hours coincident with termination of fusion. In Dulbecco's modified Eagle's medium containing 20% fetal calf serum and 8% embryo extract, the onset of fusion was delayed for 30 to 40 hours. In this medium biosynthesis of the ATPase was also delayed so that biosynthesis of the ATPase appeared to be correlated with fusion of muscle cells. Cells cultured in Culbecco's modified Eagle's medium containgin 10% horse serum, but only 60 muM Ca2+, proliferated but did not fuse. Under these conditions, synthesis of the ATPase was measurable at 50 to 60 hours, and the rate of synthesis accelerated until 120 hours when it declined. Under all conditions degradation of the ATPase occurred with a half-life of 20 hours whereas the half-life of total protein degradation was 40 hours. Synthesis of the sarcoplasmic reticulum ATPase, like that of a number of other muscle-specific proteins, is greatly accelerated as myoblasts fuse and differentiate into myotubes. Fusion is not essential for this phenomenon, however, although it is normally concomitant with it.
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PMID:Assembly of the sarcoplasmic reticulum. Biosynthesis of the adenosine triphosphatase in rat skeletal muscle cell culture. 13 98

The nature of the protein components and their location in the sarcoplasmic reticulum membrane were studied using sarcoplasmic reticulum vesicles isolated from rat skeletal muscle and purified by a density gradient centrifugation system. On the basis of analysis by means of sodium dodecyl sulfate gel electrophoresis, the protein components appear to be similar if not identical with those reported by others for rabbit sarcoplasmic reticulum, and the relative amount of each component is also similar to that found with rabbit sarcoplasmic reticulum. Evidence is presented that radioiodine-labeled diazotized diiodosulfanilic acid is a nonpermeant labeling agent of the protein components of sarcoplasmic reticulum vesicles; this agent minimally disturbs the functional activities of these membranes. By means of this labeling agent and perturbing agents, it is concluded that the protein components with molecular weights greater than 120,000 and the (Ca2+ + Mg2+)-adenosine triphosphatase partially or totally reside on or at the external surface of the sarcoplasmic reticulum vesicles. In the case of the adenosine triphosphatase, highly controlled trypsin treatment cleaves the molecule into two products, a 65,000 molecular weight fragment and a 56,000 molecular weight fragment. The evidence indicates that the 65,000 molecular weight component of the (Ca2+ + Mg2+)-adenosine triphosphatase is located in a more exposed fashion on the external surface of the vesicles than the 56,000 molecular weight compoenet and that some adenosine triphosphatase molecules have a more exposed position on the external surface of the vesicle than others. The protein components designated by MacLennan (MacLennan, D. H. (1975) Can. J. Biochem. 53, 251-261) as "calsequestrin" and "high affinity Ca2+ binding protein" are shown not to be on the external surface of the rat sarcoplasmic reticulum vesicle but rather to reside either within the core of the membrane or on the inside surface of the vesicle. The results of this study are in agreement with the model for the organization of the protein components of the sarcoplasmic reticulum membrene recently proposed by MacLennan (MacLennan, D. H. (1975) Can. J. Biochem. 53, 251-261).
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PMID:Analysis of the arrangement of protein components in the sarcomplasmic reticulum of rat skeletal muscle. 13 99

Following the formation of hyperplastic nodules at a late stage of azo dye hepatocarcinogenesis, some areas of parenchyma show an intense RNA staining, and such hyperbasophilic foci apparently develop hepatomas. Radioautographic analyses with [3H]thymidine labeling indicate the foci to be areas of continued cell proliferation, and the hepatocytes are morphologically distinguishable from the surrounding tissue. The increase of basophilia occurs simultaneously with histochemically demonstrable decreases in bound cations and concomitant increases in pyroantimonate-precipitable free cations. Thus, the phenomenon of hyperbasophilia and the ensuing alteration of cell cycle appears to be associated with changes in intracellular homeostasis. Ultrahistochemical localizations of adenosine triphosphatase and alkaline phosphatase suggest topographic alterations of membrane enzyme activities in the foci and the persistence of altered patterns during tumor progression. The developmental feature of surface adenosine triphosphatase activity has been further studied with subcultures of epithelial cells, which were derived from normal and precancerous livers. The enzyme activity of nontumorigenic cells is minimal, while a considerably high activity is detectable in situ at the outer surface of plasma membranes of tumorigenic cells. A Ca2+- Mg2+-dependent adenosine triphosphatase is identified at the cell surface, and the ectoenzyme would be a useful marker for detection of malignant liver epithelial cells.
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PMID:Ultrastructural and cytochemical studies on hyperbasophilic foci with special reference to the demonstration of cell surface alterations in hepatocarcinogenesis. 13 71

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


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