Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure for preparing highly purified brush border membranes from rabbit kidney cortex using differential and density gradient centrifugation is described. Brush border membranes prepared by this procedure were substantially free of basal-lateral membranes, mitochondria, endoplasmic reticulum and nuclear material as evidenced by an enrichment factor of less than 0.3 for (Na+ + K+)-ATPase, succinate dehydrogenase, NADPH-cytochrome c reductase and DNA. Alkaline phosphatase was enriched ten fold indicating that the membranes were enriched at least 30 fold with respect to other cellular organelles. The yield of brush border membranes was 20%. Transport of D-glucose by the membranes was identical to that previously reported except that the Arrhenius plot for temperature dependence of transport was curvilinear (EA = 11.3--37.6 kcal/mol) rather than biphasic. Transport of p-aminohippuric acid and uric acid were increased by the presence of NaCl, either gradient or preequilibrated. However, no overshoot was obtained in the presence of a NaCl gradient, and KCl and LiCl also produced equivalent stimulation of transport suggesting a nonspecific ionic strength effect. Uptakes of p-aminohippuric acid and uric acid were not saturable, and were increased markedly by reducing the pH from 7.5 to 5.6. Probenecid (1 mM) reduced p-aminohippuric acid and uric acid (50 muM) uptake by 49% and 21%, respectively. We conclude that the uptake of uric acid and p-aminohippuric acid by renal brush border membranes of the rabbit occurs primarily by a simple solubility-diffusion mechanism.
 ...
PMID:Transport of p-aminohippuric acid, uric acid and glucose in highly purified rabbit renal brush border membranes. 3 45

The activity of adenosine triphosphatase and alkaline phosphatase was investigated at the fine structural level in the cyst stages of Sarcocystis tenella parasitic in the esophagus of sheep. Alkaline phosphatase reaction was observed along the outer membrane of the parasite's pellicle. The enzymatic activity was much higher on the surface of metrocytes than that of zoites, which proved to be infectious. No reaction was noted in the interior of the parasites. However, a significant amount of alkaline phosphatase activity occurred along the inner surface of the 25 nm thick primary layer of the cyst wall. No evidence of the reaction of this enzyme was seen in the secondary cyst wall, which consisted of degenerated host cells. ATP-ase activity was found in a considerable degree along the primary cyst wall (=directly limiting the cyst's interior), whereas the ground-substance of the cyst, surrounding the parasites, is free of deposits. In the parasites ATP-ase was localized in the endoplasmic reticulum, in the perinuclear space, and between the two inner membranes of the three-layered pellicle. Only rarely a slight reaction was seen in the mitochondria of the metrocytes, which are the reproductive cells. The other organelles typical for S. tenella were free of ATP-ase. The results indicate that the enzymes studied participate in the growing process of the cysts, in which finally the infectious zoites remain in a more or less inactive state. The localizations of the enzymes corresponded with the results known from metazoa.
 ...
PMID:[Ultrastructural localization of alkaline phosphatase and ATP-ase in cyst stages of Sarcocystis tenella (Sporozoa, Coccidia) parasitic in the esophagus of sheep (author's transl)]. 12

Mucosal response of alkaline phosphatase, ATPase and disaccharidase (lactase, maltase and trehalase) activities to sex hormones were studied by comparing male and female rats and castrated males and by injecting testosterone into castrated males. Alkaline phosphatase showed a very steep gradient in the small intestine from the oral to the aboral end, whereas ATPase activity in the ileum was still about 50% of that in the duodenum. Both enzymes showed only minor sex variations and weal response to castration. Lactase and maltase had peak activities in the jejunum, but trehalase activity was nearly equally high in the duodenal mucosa as in the jejunum. Jejunal lactase activity was about 50% lower in female than in male rats and castration decreased activity in males to the same low level as found in females. The administration of testosterone to castrated male rats did not enhance activity. Maltase activity showed similar sex variation, although castration was not able to decrease activity during the test period. Trehalase activity was lower in female than in male rats. The administration of testosterone enhance activity in castrated males.
 ...
PMID:Sex variation in the activities of mucosal hydrolytic enzymes in the small intestine of the rat. 12 35

A method was developed to isolate renal basolateral membranes from cortical kidney tubule cells of single rats. The isolated membrane fraction was characterized by the measurement of marker enzyme activities and by electron microscopy. 1. After centrifugation of crude plasma membranes on a discontinuous sucrose density gradient the basolateral membranes accumulated at a sucrose density of p= 1.14-1.15 g/ml. The yield was 147 mug membrane protein/g kidney wet weight. Protein recovery was 0.1%. 2. (Na+ + K+)-ATPase was enriched 22-fold from the homogenate. The recovery was 2.6%. The (Na+ + K+)/Mg2+-ATPase ratio was 4.1. 3. The contamination by brush borders was small. Alkaline phosphatase was 1.6-fold enriched and 0.2% was recovered. Aminopeptidase was 1-fold enriched with a recovery of 0.1%. The contamination by mitochondria, lysosomes and endoplasmic reticulum was negligible. 4. In electron micrographs the basolateral membranes showed a typical triple layered profile and were characterized by the presence of junctional complexes, gap junctions or tight junctions.
 ...
PMID:Isolation of the basal and lateral plasma membranes of rat kidney tubule cells. 13 91

A procedure was developed for the analytical isolation of brush border and basal lateral plasma membranes of intestinal epithelial cells. Brush border fragments were collected by low speed centrifugation, disrupted in hypertonic sorbitol, and subjected to density gradient centrifugation for separation of plasma membranes from nuclei and core material. Sucrase specific activity in the purified brush border plasma membranes was increased fortyfold with respect to the initial homogenate. Basal lateral membrane were harvested from the low speed supernatant and resolved from other subcellular components by equilibrium density gradient centrifugation. Recovery of Na, K-ATPase activity was 94%, and 61% of the recovered activity was present in a single symmetrical peak. The specific activity of Na, K-ATPase was increased twelvefold, and it was purified with respect to sucrase, succinic dehydrogenase, NADPH-cytochrome c reductase, nonspecific esterase, beta-glucuronidase, DNA, and RNA. The observed purification factors are comparable to results reported for other purification procedures, and the yield of Na, K-ATPase is greater by a factor of two than those reported for other procedures which produce no net increase in the Na, K-ATPase activity. Na, K-ATPase rich membranes are shown to originate from the basal lateral plasma membranes by the patterns of labeling that were produced when either isolated cells or everted gut sacs were incubated with the slowly permeating reagent 35S-p-(diazonium)-benzenesulfonic acid. In the former case subsequently purified Na, K-ATPase rich and sucrase rich membranes are labeled to the same extent, while in the latter there is a tenfold excess of label in the sucrase rich membranes. The plasma membrane fractions were in both cases more heavily labeled than intracellular protein. Alkaline phosphatase and calcium-stimulated ATPase were present at comparable levels on the two aspects of the epithelial cell plasma membrane, and 25% of the acid phosphatase activity was present on the basal lateral membrane, while it was absent from the brush border membrane. Less than 6% of the total Na, K-ATPase was present in brush border membranes.
 ...
PMID:Analytical isolation of plasma membranes of intestinal epithelial cells: identification of Na, K-ATPase rich membranes and the distribution of enzyme activities. 13 16

The surface epithelium of vagina, uterovaginal region and uterus as well as the uterine and uterovaginal glands of 18 mature female quails were studied with histochemical methods. As in other avian species also in the quail a storage of spermatozoa in the lightly coiled uterovaginal glands takes place. The functional specialization of these glands is underlined by their distinct enzyme pattern. A strong reactivity of enzymes from oxidative pathways and of adenosine triphosphatase between epithelium and glandular luminal content. Alkaline phosphatase in the glandular epithelium was observed only when an egg is transported through the uterovaginal region. As in other vertebrate sperm storing sites also in the uterovaginal region of the quail the presence of a strong steroid dehydrogenase activity is registered.
 ...
PMID:[On the histotopochemistry of the uterovaginal region in the quail (Coturnix coturnix japonica) (author's transl)]. 13 47

Changes in activities of plasma membrane enzymes during liver regeneration may be related to the maintenance of hepatic function or to the regulation of cell proliferation. Plasma membranes were isolated from rat livers at various times after partial hepatectomy, and the specific activities of alkaline phosphatase, (Na+ + K+)-ATPase, leucine aminopeptidase, 5'-nucleotidase, and adenylate cyclase (basal and with glucagon or epinephrine) were measured. Alkaline phosphatase and (Na+ + K+)-ATPase activity increased 3.6-fold and 2-fold respectively, during the first 48 h after partial hepatectomy. The time of onset and duration of change suggest that these increases in activity are involved in the maintenance of bile secretion. Decreases in leucine aminopeptidase activity at 48--108 h and in 5'-nucleotidase activity at 12--24 h were observed, which may be involved in the restoration of protein and accumulation of RNA. The basal activity of adenylate cyclase increased after partial hepatectomy. The response of adenylate cyclase to epinephrine showed a transitory increase between 36 and 108 h after surgery, while the response to glucagon was decreased by approximately 50% at all time points through 324 h after surgery. These changes in the hormone responsiveness of adenylate cyclase are similar to those previously observed in fetal and preneoplastic liver.
 ...
PMID:Changes in plasma membrane enzyme activities during liver regeneration in the rat. 14 24

Brush border sucrase and lactase activities are significantly elevated in alloxan-induced chronic diabetes and are restored to control levels after insulin treatment. Alkaline phosphatase and Mg-ATPase levels remain unchanged in diabetes, compared to a control group. Insulin treatment alone to control animals also led to enhanced activities of these enzymes.
 ...
PMID:Effect of chronic alloxan diabetes and insulin administration on intestinal brush border enzymes. 14 19

Exponentially growing and stationary phase young and old cultures of the human cell line WI-38 were studied using cytochemistry at the ultrastructural level. 5'-Nucleotidase activity was present in the plasma membrane of all cells examined; in exponentially growing cultures the reaction was more intense in mitotic cells than in interphase cells. An increase in the amount of the reaction product was observed at confluencey, especially in older cells. The reaction of Mg2+-activated adenosine 5'-triphosphatase was absent or very weak in exponentially growing cells and increased at confluency, especially in older cells. Alkaline phosphatase was detectable only in the cell membranes and in intercellular spaces of young cells at confluency. Acid phosphatase activity was increased in old cells, especially at confluency. In these old cells, positive reactions appeared in numerous small lysosomes, autophagic vacuoles and in some flattened sacs of the Golgi apparatus. The obtained results confirm and extend previous biochemical observations and indicate that changes in phosphatase activity are associated with proliferative activity and senescence of cells growing in vitro.
 ...
PMID:Effect of cell density and senescence of WI-38 cells on cytochemically demonstrable phosphatases. 15 83

The existence of a membrane-bound HCO3-stimulated ATPase in intestinal mucosa is controversial. A crude brush border fraction of rat small intestinal homogenates contained HCO3-ATPase activity which was inhibited by preincubation with 3 mM EDTA. Alkaline phosphatase activity of this preparation was also inhibited in a parallel, time-dependent fashion by preincubation with EDTA. When 5 mM ZnSO4 accompanied 3 mM EDTA in the preincubation mix, preservation of both enzyme activities occurred, demonstrating a requirement of Zn for the activity of both these phosphatases. These studies support the earlier contention that HCO3-ATPase and alkaline phosphatase activities may be different properties of the same enzyme, and raise the possibility that the ATPase could play a role in intestinal ion transport. The failure to identify a membrane-bound HCO3-ATPase by other workers could be due to the exposure of EDTA which occurred in their tissue preparation.
 ...
PMID:Requirement of Zn to demonstrate HCO3-stimulated ATPase activity of rat small intestinal brush border. 15 7


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