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 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.
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PMID:Requirement of Zn to demonstrate HCO3-stimulated ATPase activity of rat small intestinal brush border. 15 7

A new procedure for isolation of the Rat jejunum and ileum brush border vesicles is described. Several calcium transport conditions have been established. A previous incubation with ATP induces an increased calcium binding. The role of a magnesium ATPase is discussed.
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PMID:[In vitro calcium binding by isolated brush border vesicles of rat jejunum and ileum]. 16 Feb 92

Free flow electrophoresis was employed to separate renal cortical plasma membranes into luminal (brush border microvilli) and contraluminal (basal-lateral membrane) fractions. During the separation adenylate cyclase activity was found to parallel the activity of Na+-K+-activated ATPase, an enzyme which is present in contraluminal but not in luminal membranes. In the basal-lateral membrane fraction the specific activities of adenylate cyclase and Na+-K+-activated ATPase were 4.4 and 4.6 times greater, respectively, than in the brush border fraction. The adenylate cyclase of the basal-lateral membrane fraction was specifically stimulated by parathyroid hormone which maximally increased enzyme activity eightfold. The biologically active (1-34) peptide fragment of paratyhroid hormone produced a 350% increase in adenylate cyclase activity. In contrast, calcitonin, epinephrine and vasopressin maximally stimulated the enzyme by only 55, 35 and 30%, respectively. These results indicate that adenylate cyclase, specifically stimulated by parathyroid hormone, is distributed preferentially in the contraluminal region of the plasma membrane of renal cortical epithelial cells.
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PMID:Distribution of parathyroid hormone-stimulated adenylate cyclase in plasma membranes of cells of the kidney cortex. 17 37

The subcellular distribution of adenyl cyclase was investigated in small intestinal epithelial cells. Enterocytes were isolated, disrupted and the resulting membranes fractionated by differential and sucrose gradient centrifugation. Separation of luminal (brush border) and contra-luminal (basolateral) plasma membrane was achieved on a discontinuous sucrose gradient. The activity of adenyl cyclase was followed during fractionation in relation to other enzymes, notably those considered as markers for luminal and contraluminal plasma membrane. The luminal membrane was identified by the membrane-bound enzymes sucrase and alkaline phosphatase and the basolateral region by (Na+ + K+)-ATPase. Enrichment of the former two enzymes in purified luminal plasma membrane was 8-fold over cells and that of (Na+ + K+)-ATPase in purified bisolateral plasma membranes was 13-fold. F--activated adenyl cyclase co-purified with (Na+ + K+)-ATPase, suggesting a common localization on the plasma membrane. The distribution of K+-stimulated phosphatase and 5'-nucleotidase also followed (Na+ + K+)-ATPase during fractionation.
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PMID:The surface membrane of the small intestinal epithelial cell. I. Localization of adenyl cyclase. 17 91

The intestinal epithelium of Ascardia galli has been studied with various cytological and cytochemical techniques. It consists of large epithelial cells resting on a thick collagenous basal lamina. Their luminal surface is provided with microvilli. The intestinal cells store considerable amounts of glycogen and neutral lipids. Some intracellular granular inclusions, which stain for proteins, phospholipids and lipoproteins, are distributed throughout the cytoplasm. The brush border is composed of microvilli whereas the outer surface coat consists of saliva resistant PAS-positive material. The detailed histochemical analysis of surface material has revealed that it is composed of nonacetylated acid mucopolysaccharides rich in hyaluronic acid with carboxylate polyanions. The brush border shows intense activities of acid phosphatase and glucose-6-phosphatase, moderate of ATPase, and lipase, weak of 5'-nucleotidase. Acid phosphatase-positive intracellular structures are seen in the intestinal epithelium which form distinct aggregations.
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PMID:Morphological and histochemical observations on the intestinal epithelium of Ascardia galli (Nematoda: Ascaridida). 21 46

In order to elucidate a possible relationship between (Na+ + K+)-activated ATPase and intestinal absorption of actively transported monosaccharides enzyme activity was measured in mucosal cells from alloxan diabetic rats. The general effect of increasing capacity of active, Na+-dependent transport processes in diabetes mellitus is associated with a significantly enhanced (Na+ +K+)-activated ATPase activity in mucosal homogenate from diabetic animals. To study the localization of these effects within the cell we isolated purified brush borders and their substructures. To enable a comparison to be made between preparation procedures of diabetic and control animals the fractions were controlled by electronmicroscopy and by measuring the sucrase activity. In the purified brush border fraction of alloxan treated rats there was no significant increase in (Na+ + K+)-activated ATPase activity. Based on these results we conclude that the (Na+ + K+)-activated ATPase in the basolateral membranes was increased in alloxan diabetes, and it seems very likely that this enzyme is involved in the regulation of Na+-dependent transport processes.
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PMID:[Effect of alloxan diabetes on (Na+ + K+)-activated ATPase in brush border membrane of the mucosal cell of rat small intestine]. 21 7

To determine the mechanism of the maturation of the brush border membrane in intestinal epithelial cells, purification of the plasma membrane from undifferentiated rat crypt cells and of the basal-lateral membrane from villous cells has been performed. The method is based on density perturbation of the mitochondria to selectively disrupt their association with the membrane. With both cell populations, two membrane subfractions displaying the same respective density on sucrose gradient have been obtained with an overall yield of 15--20% and a 10-fold enrichment of the plasma membrane markers 5'-nucleotidase and (Na+ + K+)-dependent, ouabain-sensitive ATPase chosen to follow their purification. The four fractions were constituted by sheets and apparently closed vesicles of various sizes. Each fraction was characterized by a distinct protein composition and different levels of enzyme activities. The cells, used for the preparation of the membranes, were isolated as a villus to crypt gradient. This separation and that of the membranes, led to the conclusion that the (Na+ + K+)-dependent ATPase is localized principally in the plasma membrane of all cells whatever their state of maturation, while 5'-nucleotidase is predominantly located in the basal-lateral membrane of the villous cells and may serve as a specific marker for the purification of this membrane. Finally it has been shown that aminopeptidase, dissacharidases and alkaline phosphatase do not appear simultaneously in the maturation process of the cells, alkaline phosphatase being absent from the crypt cells and aminopeptidase being the first to be synthesized. This enzyme seems to appear in the crypt cells membrane before being integrated into the mature brush border membrane.
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PMID:Plasma membranes from rat intestinal epithelial cells at different stages of maturation. I. Preparation and characterization of plasma membrane subfractions originating from crypt cells and from villous cells. 21 16

Luminal (brush border) and antiluminal (basal-lateral) membranes were isolated from canine renal cortex. The enzyme marker for luminal membrane, alkaline phosphatase was enhanced 19-fold and the antiluminal enzyme marker, (Na+ + K+)-ATPase, was enhanced 22-fold in their respective membrane preparation, while the amount of cross contamination was minimal. Contamination of these preparations by enzyme markers for lysosomes, endoplasmic reticulum and mitochondria was also low. Routinely, more than 50 mg membrane protein was isolated for each membrane. Electron micrographs showed that the membranes were uniform in size, appearance, and vesicular in nature. An examination of the orientation of these membranes showed that 76.5% of the antiluminal membranes and 86% of the luminal membranes were right-side out.
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PMID:Isolation of luminal and antiluminal membranes from dog kidney cortex. 22 Oct 18

Sodium- and potassium-dependent adenosine triphosphatase (Na+--K+-ATPase) has been demonstrated in the branchial heart appendage (pericardial gland) of Sepia officinalis L. by biochemical, cytochemical and autoradiographical methods. The biochemical data indicate the presence of Na+--K+-ATPase, judging from the potassium dependency and, with some restrictions, the inhibition by ouabain. Cytochemically and autoradiographically, the enzyme could be localized on the cytoplasmic surfaces of the lateral plasma membranes and the basal membrane infoldings (basal labyrinth) of the folded epithelium of the branchial heart appendage. The pdocytes of the peripheral zone of the organ reacted negatively. In addition to the Na+--K+-ATPase, a magnesium-activated adenosine triphosphatase (Mg2+-ATPase) was demonstrated in the folded epithelium, localized mainly in the mitochondria but also at the brush border and in the apical intercellular space, whereas a bicarbonate-stimulated ATPase (HCO-3-ATPase) was present only in the mitochondria.
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PMID:Adenosine triphosphatase localization in the branchial heart appendage of Sepia officinalis L. (Cephalopoda). 23 Jan 67

A phytohemagglutinin extract is prepared from raw kidney beans (Phaseolus vulgaris) and incorporated at a level of 1% (dry matter) in the diet of young growing rats. Beside a decrease of feed intakes, the main effects of the experimental diet are the following : growth depression, decrease of dry matter and protein digestibility and hypoglycemia. Biological value, organs weight (liver, kidneys, spleen) did not change significantly. The hemagglutinin extract induces an inhibition of saccharase activity whereas (Na+-K+)-ATPase remains unchanged. Growth depressing effect may be due to an alteration of hydrolysis and absorption mechanisms at the level of brush border of enterocytes.
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PMID:[Effects of a phytohemagglutinin extract on growth, nitrogen digestibility and the activity of invertase and (Na+-K+)-ATPase in the intestinal mucosa of the rat]. 23 10


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