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)

Brush border membrane vesicles (BBMV) and basolateral membrane vesicles (BLMV) were simultaneously prepared from surgically resected pieces of morphologically intact human duodenum with a modified Percoll gradient centrifugation method. Alkaline phosphatase was enriched 20-fold in BBMV, whereas (Na+ + K+)-stimulated adenosine triphosphatase was enriched 15-fold in BLMV. BBMV and BLMV were preincubated with 3 microM synthetic somatostatin-14 or 3 microM SMS 201-995 for 10 min at 5 degrees C. In BBMV calcium, sodium, D-glucose, L-alanine, and D-mannitol uptake was unaffected by somatostatin-14 and SMS 201-995. In BLMV we found two Ca++ transport systems: Na+/Ca++ exchange and ATP-driven Ca++ transport. Somatostatin-14 had no effect on either of the two transport mechanisms. SMS 201-995 had no effect on Na+/Ca++ exchange but significantly inhibited basolateral ATP-dependent Ca++ transport (-40% +/- 5%, p less than 0.005).
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PMID:Effect of the somatostatin analogue SMS 201-995 on ATP-dependent calcium transport of basolateral vesicles from human duodenum. 289 47

This study measured the ouabain-sensitive adenosine triphosphatase activity in sciatic nerve, lumbar dorsal root ganglia and superior cervical ganglia from control rats, rats with 8 weeks streptozotocin-induced diabetes and rats fed a diet containing 20% galactose for 8 weeks. Whilst the sciatic nerves of the diabetic rats showed a 42% reduction in ouabain-sensitive adenosine triphosphatase activity, the galactose-fed rats showed an increase of 124% (p less than 0.01 and p less than 0.005, respectively, compared to controls). There was also a reduction (by 30% compared to controls; p less than 0.05) in the ouabain-sensitive adenosine triphosphatase activity of the dorsal root ganglia from the diabetic rats, but their superior cervical ganglia did not show a significant fall. The ganglia of the galactosaemic rats showed no change in ouabain-sensitive adenosine triphosphatase activity compared to controls. These changes coexisted with increases in appropriate polyol pathway metabolites in all tissues of both diabetic and galactosaemic rats. There were also depletions of myo-inositol in the sciatic nerves and dorsal root ganglia of diabetic and galactosaemic rats, but their superior cervical ganglia contained levels of myo-inositol which were similar to those of controls. The nerves of the galactosaemic rats showed increased water content; the nerves of the diabetic rats did not. The data argue against a simple relationship between myo-inositol depletion and impaired Na/K adenosine triphosphatase activity in association with exaggerated polyol pathway flux in peripheral nervous tissue.
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PMID:Opposite effects of diabetes and galactosaemia on adenosine triphosphatase activity in rat nervous tissue. 295 44

This study measured the ouabain-sensitive and ouabain-resistant adenosine triphosphatase activity in homogenates of the sciatic nerves and of pooled fourth and fifth lumbar dorsal root ganglia from rats fed 20% galactose or made diabetic with streptozotocin for either 4 or 8 weeks. Diabetes caused reductions in both fractions of sciatic nerve adenosine triphosphatase activity. After 8 weeks the ouabain-sensitive fraction was 54% of control (p less than 0.05) and the ouabain-resistant fraction was 57% of control (p less than 0.05). Galactose feeding more than doubled the ouabain-sensitive adenosine triphosphatase activity in the sciatic nerve (225% of control after 4 weeks, 215% of control after 8 weeks of galactose feeding, both p less than 0.01) and produced a progressive increase in the ouabain-resistant fraction (119% of control at 4 weeks (p less than 0.05) and 176% of control at 8 weeks (p less than 0.01)). In a group of rats fed galactose for 5 days, sciatic nerve ouabain-sensitive adenosine triphosphatase activity was 165% of control. Treatment with the aldose-reductase inhibitors tolrestat, ponalrestat or sorbinil prevented accumulation of polyol and depletion of myo-inositol in the sciatic nerves, indicating effective inhibition of aldose reductase. These drugs prevented completely the effect of galactose on the sciatic nerve adenosine triphosphatase activity, but had no significant effect on the reduction in adenosine triphosphatase activity in the sciatic nerves of diabetic rats. In the dorsal root ganglia galactose feeding had no measurable effect on the adenosine triphosphatase activity. Diabetes caused a modest numerical reduction in the ouabain-sensitive activity only.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adenosine triphosphatase in nerves and ganglia of rats with streptozotocin-induced diabetes or galactosaemia; effects of aldose reductase inhibition. 297 Sep 84

In the present in-vitro study we investigated the possible role of the calmodulin-antagonistic drugs loperamide and calmidazolium in the regulation of transepithelial Ca2+ transport of human duodenum. Brush border membrane vesicles and basolateral membrane vesicles were simultaneously prepared from surgically resected pieces of morphologically intact human duodenum with a modified Percoll-gradient centrifugation method. Brush border and basolateral membrane vesicles were characterized using enzyme marker analysis and electron microscopy: alkaline phosphatase was enriched 20-fold in brush border membrane vesicles, whereas [Na+ + K+]-stimulated adenosine triphosphatase was enriched 15-fold in basolateral membrane vesicles. Calmodulin activity was determined by a specific radioimmunoassay after solubilizing brush border and basolateral membrane vesicles in 1% Triton X-100. In basolateral membrane vesicles, we found no calmodulin activity. In brush border membrane vesicles calmodulin activity was impaired by 50% after pre-incubation with loperamide or calmidazolium. We measured calcium, sodium, D-glucose and D-mannitol uptake with a rapid filtration technique. Before the transport experiments, brush border and basolateral membrane vesicles were pre-incubated with 5 microM loperamide or 5 microM calmidazolium for 60 min at 5 degrees C. In drug-pretreated, brush border membrane vesicles calcium uptake was significantly reduced after 1 min incubation (-25% +/- 5%, P less than 0.05); this effect was completely reversed in the presence of 5 microM calmodulin. In basolateral membrane vesicles, we found two Ca2+ transport systems: (1) Na+/Ca2+ exchange and (2) ATP-dependent Ca2+ transport. In basolateral membrane vesicles loperamide had no effect. Calmidazolium had no effect on Na+/Ca2+ exchange, but significantly inhibited ATP-dependent Ca2+ transport. This effect could not be reversed by calmodulin.
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PMID:Effect of two potent calmodulin antagonists on calcium transport of brush border and basolateral vesicles from human duodenum. 297 85

Transport of D-glucose, p-aminohippurate and tetraethylammonium has been studied using renal brush border membrane vesicles isolated from rats with uranyl nitrate-induced acute renal failure (ARF). Initial rate and overshoot magnitude of Na+ gradient-dependent D-glucose uptake were decreased in brush border membrane vesicles from ARF rats compared with normal rats, although there was no significant difference on D-glucose uptake in the presence of equilibrated Na+ between normal and ARF rats. Uptake of p-aminohippurate by membrane vesicles from ARF rats did not differ from normal membrane vesicles. Uptake of tetraethylammonium with or without an H+ gradient was decreased in membrane vesicles from ARF rats compared with normal rats. Dissipation rate of H+ gradient across brush border membranes did not differ between both groups. In vitro incubation of normal brush border membrane vesicles with uranyl nitrate caused no alteration in any substrate transport. However, enzyme activities such as (Na+ + K+)-adenosine triphosphatase in renal cortical homogenate were inhibited markedly in the presence of uranyl nitrate. These results suggest that uranyl nitrate-induced ARF caused alterations in the transport properties of renal brush border membranes and that these transport dysfunctions were not due to the direct effect of uranyl nitrate, but could be secondarily induced after the impairment of the integrity for tubular cells.
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PMID:Transport of p-aminohippurate, tetraethylammonium and D-glucose in renal brush border membranes from rats with acute renal failure. 298 96

The beta-methyl-galactoside- and galactose-specific transport systems of Escherichia coli were shown by experiments involving inhibitors and the use of an adenosine triphosphatase mutant strain to utilize adenosine 5'-triphosphate or a related compound to drive active transport. These systems were shown to be unable to use the activated-membrane state. The galactose-specific transport system was shown to behave most like a member of the binding-protein class of transport systems by its response to osmotic shock and vesicle formation. These results extended to two sugar transport systems: the correlation between the source of energy and class of transport system found by Berger (1973) for amino acid transport systems. That is, binding-protein systems utilized adenosine 5'-triphosphate whereas membrane-bound systems utilized the activated-membrane state to drive active transport.
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PMID:Source of energy for the Escherichia coli galactose transport systems induced by galactose. 428 77

The actively transported sugar D-glucose binds to brush borders disrupted with tris(hydroxymethyl)aminomethane in preference to D-mannose and L-glucose, which are not actively transported. This preferential binding of D-glucose is not dependent on either added Na(+) or adenosine triphosphatase activity stimulated by Na(+) with K(+) and Mg(2+), but it is temperature-dependent and is completely inhibited by 0.1 millimolar phlorizin and 1 millimolar mercuric chloride.
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PMID:D-glucose: preferential binding to brush borders disrupted with tris(hydroxymethyl)aminomethane. 601 48

The increased rate of glucose uptake found in cells transformed by Rous sarcoma virus was shown to be enhanced relative to the changes in uptake induced in nontransformed cells by deprivation of glucose (deprivation derepression). Glucose-specific uptake sites were distinguished from glucose-galactose sites in nontransformed cells, and the capacities for glucose uptake and for galactose uptake were increased to about the same extent by the exclusion of glucose from the cell culture medium. Deprivation derepression occurred without a requirement for new RNA or protein synthesis, suggesting that preexisting inactivate uptake sites were activated. Deprivation derepression could be mimicked by the treatment of cells with adenosine triphosphatase activators, and adenosine triphosphate levels were reduced in glucose-deprived cells and in cells treated with adenosine triphosphatase activators. Cells transformed by the Bryan strain of Rous sarcoma virus were unresponsive to addition of high concentrations of glucose, to glucose starvation, or to treatment with adenosine triphosphatase activators, and the relative capacity for glucose uptake in these transformed cells was enhanced much more than the capacity of galactose uptake. It was concluded that cells infected by the Bryan strain of rous sarcoma virus in the process of transformation selectively synthesize more sites specific for glucose uptake. Lower levels of adenosine triphosphate found in transformed cells possibly contribute to a chronic derepression of uptake sites.
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PMID:Increased glucose uptake capacity of Rous-transformed cells and the relevance of deprivation derepression. 626 Mar 48

A plasma membrane-enriched vesicle fraction has been prepared from Trypanosoma brucei by sonication and differential centrifugation on sucrose gradients. This fraction is enriched 5-fold in the plasma membrane marker enzymes adenyl cyclase (EC 4.6.1.1) and ouabain-inhibitable, (Na+ +K+)-dependent adenosine triphosphatase (EC 3.6.1.3). It is also enriched up to 14-fold in iodinated surface proteins, and up to 4-fold in (3H-mannose-labeled glycoproteins, of which the major variable surface coat glycoprotein is the main constituent. Proteins of the plasma membrane fraction and other subcellular fractions have been identified by electrophoretic analysis in sodium dodecyl sulfate-polyacrylamide gradient slab gels. Several high molecular weight surface glycopeptides have been selectively investigated and partially characterized by a combination of metabolic labeling with [3H]mannose, lactoperoxidase-catalyzed surface iodination, and affinity chromatography on Con A-Sepharose. In addition to the major variable surface coat glycoprotein (estimated Mr = 58000), there are several minor surface glycopeptides (Mr = 76000, 86000 and 92000-100000) which are apparent extrinsic membrane components, and two surface glycopeptides (Mr = 42000 and 130000) which are intrinsic membrane components.
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PMID:Identification and partial characterization of plasma membrane polypeptides of Trypanosoma brucei. 628 66

1 The effect of (+/-)-, (+)- and (-)-verapamil on the Ca2+-binding, Ca2+-transporting activity, and Ca2+-dependent adenosine triphosphatase (ATPase) activity of isolated cardiac sarcolemmal preparations was studied. Enzymatic treatment was used to establish the nature of the sites facilitating [14C]-(+/-)-verapamil binding. 2 (+/-)-Verapamil 1 microM inhibited the passive binding of 45Ca2+. The (+/-)- and (-)-isomers were equiactive. 3 (+/-)-Verapamil 1 microM inhibited the ATP-dependent transport of 45Ca2+ and the associated activation of the Ca2+-sensitive ATPase. The activity resided in the (-)-isomer. 4 Lineweaver-Burk plots for the initial rates of ATP-dependent transport showed that the inhibition induced by the (-)-isomer was accompanied by a reduced Km and Vmax. 5 Enzymatic removal of N-acetyl neuraminic acid and galactose residues increased [14C]-(+/-)-verapamil binding; removal of N-acetylglucosamine and treatment with phospholipase C and trypsin decreased the binding. 6 These results have been interpreted to mean that (-)-verapamil interferes with the ATP-dependent Ca2+-transporting properties of the sarcolemma, and that this effect is accompanied by an altered activity of the intrinsic Ca2+-sensitive ATPase. N-acetylneuramic acid and galactose residues do not provide binding sites for verapamil at the cell surface.
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PMID:The effect of verapamil on the Ca2+-transporting and Ca2+-ATPase activity of isolated cardiac sarcolemmal preparations. 645 Dec 52


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