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)

Hepatocytes from rats were isolated by treatment with trypsin and cultured. Plasma membranes at different culture stages were observed by electron microscopy. The activities of 5' nucleotidase and adenosinetriphosphatase on the plasma membranes were examined. The cell coat was also studied by use of the concanavalin A-peroxidase technique. The surfaces of single cells, covered with microvilli, are the site of adenosinetriphosphatase activity only and are devoid of 5'-nucleotidase activity. After a few h of culture, the cells are grouped together in tight clusters or long trails and are separated by an intercellular space of 250 A, partially permeable to lanthanum nitrate. The juxtaposed plasma membranes on which 5'-nucleotidase and adenosinetriphosphatase activities occur also delimit spaces similar to bile canaliculi. The formation of junction complexes and their permeability to lanthanum nitrate was also studied. No enzymatic activity is observed at the junctions. The numerous tight junctions, impervious to the tracer, are always accompanied by a profusion of microfilaments. Mature desmosomes are rare, and are present only in the form of "maculae adhaerentes diminutae." The gap junctions, nearly always permeable to the tracer, form rapidly and assume a variety of shapes (trail, bulge and ring-like), the significance of which is open to discussion. The use of concanavalin A permits localization of the free sugar sites on the surface of the cells, in the pinocytotic vesicles and in the internal space of the gap junctions.
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PMID:Differentiation of the plasma membrane of hepatic cells in monolayer cultures. 13 45

The luminal plasma membrane of calf urinary bladder epithelium (urothelium) has been isolated by a method designed to preserve enzymic activity as well as structural integrity. The yield was about 80 micrograms per calf bladder. Low levels of 5' nucleotidase, Mg2+-ATPase and (Na+ + K+)-ATPase activities were found in the luminal membrane fraction. Cerebroside was the major lipid present and dodecyl sulphate gel electrophoresis revealed a complex protein and glycoprotein composition in the whole membrane. A membrane fraction consisting of only the plaque areas was shown to have a simpler protein composition with major polypeptides of apparent Mr 12 000 and 22 000. These may associate to form a 30 000 apparent Mr complex which could represent the individual 'particles' of the dodecameric subunits seen by electron microscopy in the plaque regions.
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PMID:The isolation and analysis of the luminal plasma membrane of calf urinary bladder epithelium. 49 98

The ontogeny of reticular cells in the ileal Peyer's patch of sheep from 70 days gestational age was studied by light and electron microscopy and by enzyme histochemistry. Small to medium-sized lymphocytes were seen in the lamina propria at 97 days, when the stroma was essentially still mesenchymal. By 110 days, the stromal cells in the dome/follicle primordia had differentiated into reticular fibroblasts, whose processes and fibers were seen to surround groups of lymphocytes. With advancing age the number and size of primordia increased, and proliferation was obvious among the lymphocytes. Processes of reticular cells increased in number and penetrated between individual lymphocytes of the groups. Coarser desmosome-like contacts were seen between the reticular cells from 115 days onwards. A central light area in the follicle was apparent from 130 days onwards. The fine structure of the stromal cells in this light follicle center developed towards but never became similar to that of follicular dendritic cells in a typical germinal center. The fine interdigitating end branches of the stromal cells were less numerous, and the dense homogeneous material present in between the end branches was not observed in the ileal Peyer's patch follicle. Instead, small particles and vesicles were seen between the various cell types of the light center and were not restricted to the intercellular spaces between the stromal cells. In the dark peripheral zone of the follicle, the stromal cells retained more immature features. The follicle became bordered by a capsule at an early stage. This capsule was formed by multiple layers of flattened fibroblasts separated by small amounts of intercellular material only. The alkaline phosphatase, Mg(2+)-dependent adenosine triphosphatase and 5' nucleotidase reactivities of the follicular dendritic cells in the ileal Peyer's patch were similar to those of early prenatal primary follicles of sheep lymph nodes. This study indicates that the stromal cells of the ileal Peyer's patch are mesenchymal in nature and different from those of germinal centers and the epithelial stromal cells of bursa Fabricii of birds.
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PMID:Ontogeny of reticular cells in the ileal Peyer's patch of sheep and goats. 165 25

Surface antigens of adult filarial parasite S. digitata was isolated by employing techniques from manual dissection to treatment with detergents. Among the surface antigen preparations (SAPs), the activities of marker enzymes such as alkaline phosphatase, adenosine triphosphatase and 5' nucleotidase were higher with that isolated by triton X-100 technique (SAP2). On SDS-PAGE, the SAP2 has three major proteins with molecular weights 17, 29 and 36 KD which were consistent with the PBS soluble cuticular proteins (SAP1). Besides these, few other minor protein bands were also observed with the other SAPs. All SAPs were antigenic and showed positive reaction against antiserum to SAP2, and the results confirmed the SAP2 as a better preparation. The release of 29 KD surface protein during in vitro culture of adult parasite and its cross-reactivity with antiserum to surface antigens revealed the possible natural shedding of surface molecules into the host system.
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PMID:Isolation and analysis of surface antigens of filarial nematode Setaria digitata. 176 14

Microsomes from ventral prostate of 24-h castrated rats contain a single set of tissue-specific high-affinity, low-capacity androgen binding sites. These sites are indigenous to the endoplasmic reticulum, as shown by purification procedures associated with marker enzymes and electron microscopic analyses. When prostatic microsomal membranes are separated from plasma membranes using the nuclear or the mitochondrial pellets as the source of fractionation in sucrose gradients, the androgen binding activity is selectively associated with fractions rich in rough endoplasmic reticulum and ribosomes. Eighty-four percent of the total content of Na+/K+ adenosine triphosphatase (ATPase) and only 27% of the total binding capacity were concentrated in fractions rich in smooth-surfaced vesicular membranes, when nuclear suspensions constituted the membrane source. In contrast, the region of the same gradient when enriched in rough endoplasmic reticulum and deficient in plasma membrane content contained 73% of the androgen-binding capacity and only 14% of the ATPase. For fractions collected using mitochondrial suspensions as starting material, the ratio (total glucose-6-phosphatase/total binding capacity) was closer to 1.0 than similar ratios of ATPase/binding capacity, indicating co-sedimentation of binding sites with microsomal membranes and not with plasma membranes. Na+/K+ ATPase, but not 5' nucleotidase, is a valid plasma membrane marker for ventral prostate. Microsomal androgen receptors may constitute a new level of regulation of androgen action in target cells.
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PMID:Association of androgen binding sites with the endoplasmic reticulum of rat ventral prostate. 233 29

The malignant fibrous histiocytomas (MFHs) are a histologically heterogeneous group of sarcomas that have been postulated to be derived from, or have the capacity to differentiate into, histiocytes. To determine whether MFH tumor cells actually express the features of histiocytes, i.e., bone marrow-derived cells of monocyte-macrophage lineage, we studied the antigenic and enzymatic phenotype of 13 MFHs in situ using frozen and plastic sections, respectively. Five pleomorphic three fibrous, two myxoid, two giant cell, and one histiocytic MFH were studied. While tumor cells in 12 of 13 cases were positive for HLA-A,B,C, tumor cells in all cases failed to express antigens present on bone marrow-derived macrophages, i.e., leukocyte common antigen (L3B12), HLA-DR, Leu-M3, and Leu-3a. Interestingly 8 of 13 cases were positive for CALLA. Although nonspecific, this may prove useful in differential diagnosis. Enzyme histochemistry demonstrated that tumor cells in 9 of 13 cases were positive for membrane 5' nucleotidase (5'N+). Four of these were also alkaline phosphatase positive (ALKP+). All cases were either negative or weakly positive for acid phosphatase (ACIDP) and alpha-naphthyl acetate esterase (ANAE). Tumor cells were unreactive for alpha-naphthyl butyrate esterase (ANBE) and adenosine triphosphatase (ATP). These findings indicate that MFH tumor cells do not express the enzymatic profile of cells of monocyte/macrophage lineage which are membrane 5'N-/ALKP- and ACIDP+/ANAE+/ANBE+/ membrane ATP+. In fact, these data suggest a similarity to fibroblasts which are membrane 5'N+, variably ALKP+, weakly ACIDP+/ANAE+, and ANBE-/membrane ATP-. Osteoclast-like giant cells present in two cases did express a histiocytic phenotype, suggesting that they are reactive elements not derived from admixed tumor cells. These results suggest that MFHs are primitive mesenchymal neoplasms, most likely sarcomas composed of poorly differentiated fibroblasts, and are unrelated to true histiocytic neoplasms.
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PMID:Malignant fibrous histiocytoma tumor cells resemble fibroblasts. 301 Jul 48

Controversy has recently developed over the surface distribution of Na+,K+-ATPase in hepatic parenchymal cells. We have reexamined this issue using several independent techniques. A monoclonal antibody specific for the endodomain of alpha-subunit was used to examine Na+,K+-ATPase distribution at the light and electron microscope levels. When cryostat sections of rat liver were incubated with the monoclonal antibody, followed by either rhodamine or horseradish peroxidase-conjugated goat anti-mouse secondary, fluorescent staining or horseradish peroxidase reaction product was observed at the basolateral surfaces of hepatocytes from the space of Disse to the tight junctions bordering bile canaliculi. No labeling of the canalicular plasma membrane was detected. In contrast, when hepatocytes were dissociated by collagenase digestion, Na+,K+-ATPase alpha-subunit was localized to the entire plasma membrane. Na+,K+-ATPase was quantitated in isolated rat liver plasma membrane fractions by Western blots using a polyclonal antibody against Na+,K+-ATPase alpha-subunit. Plasma membranes from the basolateral domain of hepatocytes possessed essentially all of the cell's estimated Na+,K+-ATPase catalytic activity and contained a 96-kD alpha-subunit band. Canalicular plasma membrane fractions, defined by their enrichment in alkaline phosphatase, 5' nucleotidase, gamma-glutamyl transferase, and leucine aminopeptidase had no detectable Na+,K+-ATPase activity and no alpha-subunit band could be detected in Western blots of these fractions. We conclude that Na+,K+-ATPase is limited to the sinusoidal and lateral domains of hepatocyte plasma membrane in intact liver. This basolateral distribution is consistent with its topology in other ion-transporting epithelia.
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PMID:Localization of Na+,K+-ATPase alpha-subunit to the sinusoidal and lateral but not canalicular membranes of rat hepatocytes. 303 85

Attempts to identify mechanisms by which calcium antagonists might influence intracellular metabolism have not yet yielded conclusive findings. In this study bepridil, verapamil, nifedipine, and nisoldipine were found to have no influence on the rate of rat heart myosin adenosine triphosphatase or the calcium dependence of myofibrillar adenosine triphosphatase. None of these calcium antagonists alters the rate of reaction of any of the adenine nucleotide catabolic or adenosine salvage enzymes, adenylate kinase, creatine kinase, adenosine kinase, adenosine deaminase, or 5' nucleotidase, in extracts of rat heart. All four compounds, however, reduced, apparently in a non-specific manner, the rate of uptake of adenosine by myocytes isolated from rat heart. It is concluded that calcium antagonists may, through intercalation with the sarcolemmal membrane, inhibit efflux of adenosine formed by catabolism of adenine nucleotides in ischaemic myocytes. This might offer therapeutic advantage since the intracellular concentration of adenosine would thereby be increased, allowing an increased rate of incorporation of adenosine into the adenosine triphosphate pool in reoxygenated myocardium.
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PMID:Calcium antagonists and adenine nucleotide metabolism in rat heart. 349 85

Several approaches were adopted for the disruption and removal of the tegumental surface from protoscoleces of the horse strain of the hydatid organism, Echinococcus granulosus. The effectiveness of each method and the purity of subsequent microthrix-enriched fractions obtained by differential centrifugation were evaluated by electron microscopy, by the amount of protein released and by the degree of enrichment of surface plasma membrane marker enzymes. Incubation in saponin for 10 min produced the purest microtriche preparation, but in low yield; freeze/thawing, incubation in Triton X-100 for 10 min or in saponin for 20 min produced fractions containing significant amounts of relatively pure microtriches, but mild homogenization was a poor method for surface disruption and subsequent isolation of microtriches. Phosphodiesterase, adenosine triphosphatase (total and ouabain-inhibited), leucine aminopeptidase and glutamyltransferase were active in the protoscoleces but none were enriched in any of the microthrix fractions. In contrast, alkaline phosphatase, acid phosphatase, 5' nucleotidase and maltase were enriched significantly in all of the isolated microtriche preparations, which suggests that these enzymes are predominantly surface membrane bound. The protein profiles of the microthrix-enriched fractions, following SDS-PAGE, were basically similar, although there were some qualitative and quantitative differences in the proteins released by each isolation procedure. Three major PAS-staining components were present in all the preparations and these probably originated from the glycocalyx. One of these PAS-positive components, with an approximate molecular weight of 110 kDa, may be a glycoprotein specific to the horse strain of E. granulosus.
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PMID:Isolation, fractionation and partial characterization of the tegumental surface from protoscoleces of the hydatid organism, Echinococcus granulosus. 398 50

In order to get precise information about the movement of plasma membrane proteins in cap formation, cyto- and bio-chemical analyses were made of the plasma membranes from non-capped areas of Ehrlich ascites tumor cells (EATCs) exposed to concanavalin A (Con A). Blebs formed by treatment with cytochalasin B (CB) of the non-capped areas of cells having a cap were isolated and used as the plasma membranes from non-capped areas (ConA-CB-bleb fraction). This bleb fraction was compared with a bleb fraction prepared from cells without ConA-treatment (CB-bleb fraction). Cytochemical analysis of ConA-CB-bleb fraction revealed a decreased in conA binding sites (ConA-BS) compared to the CB-bleb fraction. SDS polyacrylamide slab gel electrophoresis also revealed a decrease in the major components of ConA-BS of the ConA-CB-bleb fraction. The minor components of ConA-BS showed no distinct quantitative difference between the ConA-CB-bleb and CB-bleb fractions. NA+ K+-adenosine triphosphatase (ATPase), 5' nucleotidase (5'ND) and gamma-glutamyl transpeptidase (gamma-GTP) did not show any decrease in activity in the ConA-CB-bleb fraction, but the activity of D+-stimulated phosphatase (K-Pase) was decreased. The findings indicate that there are two types of plasma membrane glycoproteins in EATCs; one includes those participating in cap formation due to ConA, e.g. the major components of ConA-BS and K-Pase, and the other, those not participating in such cap formation, e.g. some minor components of ConA-BS, ATPase, 5'ND and gamma-GTP, which keep their places without moving.
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PMID:Movement of plasma membrane proteins of Ehrlich ascites tumor cells in relation to cap formation induced by concanavalin A: a study on the non-capped areas. 611 90


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