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

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe the ultrastructure of various types of gastric carcinoma cells as well as their histochemical properties as visualized at the electron-microscope level. The histochemical properties of tumour cells were compared with those of homologous normal epithelial cells. The localization and activity of ATPase, IDPase, acidic phosphatase and alkaline phosphatase as well as of the oxidoreductases (cytochrome oxidase, succinate dehydrogenase and NADH-dehydrogenase) were studied. Our findings demonstrated that, in tumour cells, a complicated process of structural-functional restructuring takes place. It seems that a number of ultracytochemical properties may be preserved or may disappear altogether; also, such properties may become enhanced or weaker. This heterogeneity of the histochemical properties of tumour cells is discussed with regard to the role of the stem (polypotent) cell in the process of the histogenesis (cytogenesis) of human gastric carcinomas.
...
PMID:Ultrastructural ultracytochemical investigation of human gastric carcinomas. 301 11

We investigated mechanisms of mitochondrial phototoxicity caused by the cationic cyanine dye N,N'-bis(2-ethyl-1,3-dioxylene)kryptocyanine (EDKC), examining the role of the mitochondrial membrane potential on the dye uptake by carcinoma cells in vitro, and both the dark and photosensitizing effects of the dye on the function of isolated mouse liver mitochondria. When human bladder carcinoma cells (EJ) were pretreated with 2,4-dinitrophenol or nigericin, cellular uptake of EDKC decreased or increased, respectively, consistent with dye uptake that is dependent on membrane potentials. In isolated liver mitochondria, during NADH linked substrate oxidation (using glutamate plus malate or beta-hydroxybutyrate as substrates), low concentrations of the dye (0.25-0.5 microM) sensitized mitochondria to illumination with long wavelength light and inhibited both basal and ADP-stimulated respiration. Similar effects were observed during succinate oxidation, but only at higher concentrations of EDKC (greater than 5 microM) and at 10-fold greater light doses. NADH coenzyme Q reductase (Complex I) activity was inhibited by dye with or without light to an extent comparable to the inhibition of glutamate plus malate oxidation. Activity of cytochrome c oxidase, the terminal enzyme in the electron transport chain, was photosensitized with high dye doses (greater than 5 microM) and light, but the extent of inhibition was much less than the inhibition of respiration with succinate as substrate. ATP synthetase (F0F1 ATPase) activity was minimally affected by 4.0 microM EDKC with or without 24 J/cm2 light. We conclude that at low concentrations of dye, respiratory Complex I is a primary target for EDKC dark and light-induced toxicities. If Complex I is bypassed by using succinate as a respiratory substrate, the mitochondria can tolerate much higher dye concentrations and light doses.
...
PMID:Mechanisms of mitochondrial photosensitization by the cationic dye, N,N-bis(2-ethyl-1,3-dioxylene)kryptocyanine (EDKC): preferential inactivation of complex I in the electron transport chain. 311 97

Study of the products secreted by pancreatic ductal cells and analysis of the mechanisms involved in the discharge of these products have been limited by a lack of in vitro models available to experimentally approach this problem. To this aim, this investigation has been designed to determine if a human pancreatic carcinoma cell line of ductal origin (PANC-1) has maintained some of the differentiated characteristics of normal mammalian pancreatic ductal epithelium. Morphological and immunocytochemical studies indicated that, similar to isolated rat pancreatic ducts, the PANC-1 cell line contained (a) intermediate filaments of the epithelial class, (b) a basolateral plasma membrane localization of Na+, K+-ATPase, (c) complete tight junctions based on freeze-fracture analysis, (d) a cuboidal morphology when grown on Type I collagen-coated nitrocellulose filters or isolated amnion basement membrane, and (e) normal ductal epithelial ultrastructural features. Biochemical analysis indicated that, also similar to isolated rat and human pancreatic ducts, the PANC-1 cell line contained (a) gamma-glutamyltranspeptidase, (b) carbonic anhydrase, and (c) Na+, K+-ATPase based on [3H]ouabain binding assays. Comparative studies with other transformed lines indicated that PANC-1 cells have similarities to ductal lines such as MDCK cells but are markedly different from mesenchymally derived lines such as L cells. In addition, as with isolated rat and human ducts, PANC-1 cells synthesize and secrete sulfated proteins with a MW range of approximately 180K to 1 million daltons, with the predominant species being 660K daltons as indicated by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis. These results indicate that the PANC-1 cell line has maintained at least some of the differentiated characteristics of normal pancreatic ductal epithelial cells and may be a useful system for study of ductal secretory products as well as the mechanisms involved in the discharge of these products.
...
PMID:Morphological and biochemical characterization of a human pancreatic ductal cell line (PANC-1). 314 17

Resistance of human cancer cells to multiple cytotoxic hydrophobic agents (multidrug resistance) is due to overexpression of the "MDR1" gene, whose product is the plasma membrane P-glycoprotein. Plasma membrane vesicles partially purified from multidrug-resistant human KB carcinoma cells, but not from drug-sensitive cells, accumulate [3H]vinblastine in an ATP-dependent manner. This transport is osmotically sensitive, with an apparent Km of 38 microM for ATP and of approximately equal to 2 microM for vinblastine. The nonhydrolyzable analog adenosine 5'-[beta, gamma-imido]triphosphate does not substitute for ATP but is a competitive inhibitor of ATP for the transport process. Vanadate, an ATPase inhibitor, is a potent noncompetitive inhibitor of transport. These results indicate that hydrolysis of ATP is probably required for active transport of vinblastine. Several other drugs to which multidrug-resistant cell lines are resistant inhibit transport, with relative potencies as follows: vincristine greater than actinomycin D greater than daunomycin greater than colchicine = puromycin. Verapamil and quinidine, which reverse the multidrug-resistance phenotype, are good inhibitors of the transport process. These results confirm that multidrug-resistant cells express an energy-dependent plasma membrane transporter for hydrophobic drugs, and establish a system for the detailed biochemical analysis of this transport process.
...
PMID:ATP-dependent transport of vinblastine in vesicles from human multidrug-resistant cells. 336 66

Purified glycolipids were tested for their ability to serve as acceptors of [14C]fucose from GDP-[14C]fucose as catalyzed by cell-free extracts and purified membrane fractions of human colorectal carcinoma cells, SW1116, cultured in serum-free medium. Purified lactotetraosyl ceramide (Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc-Cer or LcOse4Cer) and H-1 glycolipid (Fuc alpha 1----2Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc-Cer or IV2 Fuc alpha LcOse4Cer) stimulated incorporation of radioactivity into lipid-soluble glycolipid at a rate greater than ten times that of Lea glycolipid [Gal beta 1----3(Fuc alpha 1----4)GlcNAc beta 1----3Gal beta 1----4Glc-Cer or III4 Fuc alpha LcOse4Cer]. The enzymatic activities in crude and purified membrane fractions were optimized for substrate concentrations (glycolipid and GDP-fucose), detergent requirement (taurocholate), pH, time and protein. The radioactive product of H-1 fucosylation migrated as discrete and distinct bands on high-performance thin-layer chromatograms (HPTLC). Evidence for their identity with Leb fucolipid described previously [Fuc alpha 1----2Gal beta 1----3(Fuc alpha 1----4)GlcNAc beta 1----3Gal beta 1----4Glc-Cer or III4IV2 (Fuc alpha) LcOse4Cer] is presented. The radioactive product of LcOse4Cer fucosylation was mainly Lea fucolipid as determined by co-migration with authentic Lea fucolipid in three HPTLC systems as native and acetylated derivatives. Our results also indicated a low level of H-1 and Leb glycolipid synthesis from LcOse4Cer. On the basis of the optima, linearity for time, and enzyme-limiting conditions, we obtained a 12-19-fold purification of the LcOse4Cer and H-1 fucosyl transferase acceptor activities in three peaks of a sucrose gradient. The peak with the highest specific activity (peak 3) was highest in density and in Na+, K+, ATPase specific activity, although NADH-cytochrome-c reductase and UDP-GalNac transferase were also present in peak 3. The apparent Km values of LcOse4Cer acceptor activity and H-1 acceptor activity in peak 3 were significantly different (p less than 0.01) by statistical tests, 2.4 microM and 0.5 microM, respectively. These apparent Km values were much lower (10(3) X) and the pH optima were lower (4.8-5.3), than the corresponding properties reported for the alpha 1----3/alpha 1----4 fucosyl transferase purified from human milk. Our results suggest a role for the non-glycosidic moieties of the acceptors and/or the tissue-specific or primitive expression of these fucosyl transferase activities.
...
PMID:Biosynthesis of Lewis fucolipid antigens in human colorectal carcinoma cells. Partial characterization of LcOse4Cer and H-1 fucolipid fucosyl transferase acceptor activities. 366 17

Deoxythymidine-5'-triphosphatase (dTTPase) from human serum was separated by DEAE-cellulose chromatography from unspecific hydrolases in a single step. The method was adapted to a microscale and the enzymatic activity was determined for five different groups of patients including epithelial carcinoma, leukemia and three control groups. The result is that the purified dTTPase preparations of these groups reflect the situation obtained in the whole serum.
...
PMID:A one-step liquid-chromatographic technique for the estimation of the deoxythymidine-5'-triphosphatase in human serum. 609 26

Plasma membrane vesicles of Ehrlich ascites carcinoma cells have been isolated to a high degree of purity. In the presence of Mg2+, the plasma membrane preparation exhibits a Ca2+-dependent ATPase activity of 2 mumol Pi per h per mg protein. It is suggested that this (Ca2+ + Mg2+)-ATPase activity is related to the measured Ca2+ transport which was characterized by Km values for ATP and Ca2+ of 44 +/- 9 microM and 0.25 +/- 0.10 microM, respectively. Phosphorylation of plasma membranes with [gamma-32P]ATP and analysis of the radioactive species by polyacrylamide gel electrophoresis revealed a Ca2+-dependent hydroxylamine-sensitive phosphoprotein with a molecular mass of 135 kDa. Molecular mass and other data differentiate this phosphoprotein from the catalytic subunit of (Na+ + K+)-ATPase and from the catalytic subunit of (Ca2+ + Mg2+)-ATPase of endoplasmic reticulum. It is suggested that the 135 kDa phosphoprotein represents the phosphorylated catalytic subunit of the (Ca2+ + Mg2+)-ATPase of the plasma membrane of Ehrlich ascites carcinoma cells. This finding is discussed in relation to previous attempts to identify a Ca2+-pump in plasma membranes isolated from nucleated cells.
...
PMID:Identification of Ca2+-pump-related phosphoprotein in plasma membrane vesicles of Ehrlich ascites carcinoma cells. 613 90

K+-dependent, ouabain-sensitive nitrophenyl phosphatase (K+-NPPase) activity, which reflects the terminal dephosphorylation step of (Na+ + K+)-ATPase action, was studied histochemically in human thyroid normal follicular cells and in human thyroid carcinoma cells, using a newly developed one-step lead citrate method. In normal thyroid follicular cells, reaction product for K+-NPPase activity was found on the lateral plasma membrane and not on either the apical or basal plasma membrane. In thyroid carcinoma cells, a large amount of reaction product was observed on the lateral plasma membrane and also on the apical and basal plasma membrane. Appropriate control experiments indicated that the deposition of reaction product was K+ dependent and ouabain sensitive. Although there was some overlap in the distribution of reaction products for K+-NPPase and Mg2+-ATPase, significant differences were consistently observed. The biochemical findings indicated that the K+-NPPase activity per milligram of DNA in thyroid carcinoma cells was approximately 10 times higher than that in normal thyroid cells, and that a significant positive correlation exists between K+-NPPase and (Na+ + K+)-ATPase activity. The physiologic and pathologic implications of this localization for tracing the route of active Na+ transport, which might participate in the transport of iodide ion in both human thyroid normal follicular cells and human thyroid carcinoma cells, are discussed.
...
PMID:Changes in localization of ouabain-sensitive, potassium-dependent p-nitrophenylphosphatase activity in human thyroid carcinoma cells. 613 23

ATPase histochemistry was used to examine Langerhans cell (LC) populations in the skin of young persons with no evidence of solar damage and older adults with chronic actinically damaged skin. The number of LC was significantly decreased in the older age group. Significantly fewer LC were observed in exposed vs covered skin in the older individuals; no such disparity was noted in the younger subjects. Morphologic alterations in ATPase-positive cells were noted in some specimens, most of which were taken from the exposed skin of elderly persons. The results suggest an independent, although possibly additive, quantitative and qualitative influence of aging and chronic sun exposure on the LC population. Decreased numbers of LC in the sun-damaged skin of elderly individuals may play a critical permissive role in the development of cutaneous carcinoma.
...
PMID:The effect of aging and chronic sun exposure on human Langerhans cell populations. 619 32

Adenosine triphosphatase (ATPase) activity and acid phosphatase activity in lymphocytes from patients with carcinoma of the gastrointestinal tract were determined in order to investigate whether or not changes in these enzyme activities has any relation to the immune reactivity of carcinoma-bearing patients. In patients with a performance status of more than 60%, the mean value of the total ATPase activity in lymphocytes differed little from that in controls, but the mean value of the oligomycin-sensitive ATPase activity decreased as compared to that in the controls. On the other hand, the mean values of the activities of both free and total acid phosphatase in lymphocytes increased as compared to those in controls. The mean values of the activities of both ATPase and acid phosphatase in lymphocytes from patients whose performance status was less than 50% decreased as compared to those from controls and patients whose performance status was more than 60%. The change of the activities of both ATPase and acid phosphatase in lymphocytes has relation to that of the immunological parameters of the patients with carcinoma of the gastrointestinal tract. These results indicate that both ATPase and acid phosphatase in lymphocytes may play an important role in the immune mechanism.
...
PMID:Changes of enzyme activities recognized in lymphocytes from patients with carcinoma of the gastrointestinal tract. 622 54


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---