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:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male mice of 7 different strains were injected i.p. with 400 mg/kg of butylated hydroxytoluene (BHT). 2 and 4 days later, the incorporation of thymidine into pulmonary DNA was significantly increased in all treated animals and this was accompanied by an increase in lung weight and pulmonary DNA. Thymidine kinase activity and DNA polymerase activity were enhanced in the lungs of BHT-treated animals and maximum activity of these enzymes appeared to precede maximum thymidine incorporation by 24 h. 3 days after BHT a good correlation was found between administered dose and thymidine kinase activity. Measuring the activity of this enzyme might serve as a convenient biochemical marker to follow and to quantitate BHT-produced cell proliferation in lung. The concentrations of cyclic AMP and the activity of adenylate cyclase were not altered by BHT on days 1-9 after administration. BHT produced also some dose-dependent, time-dependent increases in the activities of pulmonary 5'-nucleotidase and glucose-6-phosphate dehydrogenase (G6PDH), but had little effect on isocitric dehydrogenase (ICDH), pyruvate kinase (PK) and lactic dehydrogenase (LDH).
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PMID:Biochemical paramters of BHT-induced cell growth in mouse lung. 124 55

Studies have demonstrated that augmenting the omega 6 polyunsaturated-fatty-acid (PUFA) content of N1E-115 neuroblastoma cells by media supplementation with linoleic acid results in greater than or equal to 2-fold increases in basal levels of intracellular cyclic AMP (cAMP). Data suggested some involvement of increased production of adenosine from endogenous metabolites; however, increases in adenosine were not related to increased activity of 5'-nucleotidase or decreased uptake of extracellular adenosine. PUFA-dependent elevations in basal cAMP were evident within 1 min of exposure to a phosphodiesterase inhibitor; this phenomenon did not appear to be due to PUFA-dependent changes in Ca2+ uptake or to increases in sensitivity of adenylate cyclase to Ca2+. Forskolin-stimulated cAMP formation was 3-fold higher in PUFA-enriched cells than in control cells, which suggested a direct effect on the functioning of the catalytic unit. Linoleic acid supplementation resulted in a 2-fold increase in the maximum amounts of cAMP produced in response to the stable adenosine analogue, 5'-N'ethylcarboxy-amidoadenosine (NECA). The altered stimulatory response did not involve eicosanoid formation, but may have been related to an increase in the number of stimulatory adenosine receptors, as judged by binding of [3H]NECA. These studies indicate that membrane PUFA modulate adenosine-related functions in neuroblastoma cells, and suggest that a complex series of mechanisms is involved in this regulation.
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PMID:Non-eicosanoid functions of essential fatty acids: regulation of adenosine-related functions in cultured neuroblastoma cells. 132 28

The ecto-5'-nucleotidase activity of rat glomerular mesangial cells increases after exposure to prostaglandin E2 (PGE2) via cAMP stimulation (Savic et al., 1990, Immunology 70, 321). Therefore we examined whether other cAMP-stimulating agents had a similar effect. Forskolin (1 microM), PGE2 (10 microM), and isoproterenol (10 microM), three products stimulating rat mesangial cell adenylate cyclase activity, enhanced cAMP accumulation within 5 min and 5'-nucleotidase activity after a lag time of at least 24 h, 3-Isobutyl-1-methylxanthine (IBMX) and Ro 20-1724, two drugs inhibiting cAMP degradation, also stimulated cAMP accumulation and 5'-nucleotidase activity. The effects of these agents on 5'-nucleotidase activity were additive with those of the three products stimulating adenylate cyclase activity, except for Ro 20-1724 and forskolin which acted synergistically. Cycloheximide, a blocker of protein synthesis, suppressed the cAMP-dependent increase of 5'-nucleotidase activity. Because ecto-5'-nucleotidase activity is a marker of cell differentiation, the effect of the same cAMP-stimulating agents on cell proliferation was also studied. Forskolin, PGE2, and isoproterenol inhibited [3H]thymidine incorporation into rat mesangial cells in a dose-dependent manner. The same effect was obtained with IBMX (100 microM) and Ro 20-1724 (50 microM). Stimulation of 5'-nucleotidase activity and inhibition of [3H]thymidine incorporation occurred over the same range of concentrations for the various agonists tested. Taken together, these results indicate that expression of ecto-5'-nucleotidase in rat mesangial cells is induced by cAMP whatever the reason for its accumulation. The simultaneous inhibition of DNA synthesis may occur independently or be associated with the stimulation of 5'-nucleotidase expression.
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PMID:Cyclic adenosine monophosphate-stimulating agents induce ecto-5'-nucleotidase activity and inhibit DNA synthesis in rat cultured mesangial cells. 165 63

The orientation of the enzyme Mg(2+)-ATPase (EC 3.6.1.3) in the transverse tubule (TT) membranes of skeletal muscle was investigated using highly purified chicken and rabbit TT vesicles. The percentage of sealed vesicles present in these preparations averaged 88 and 78%, respectively, as calculated from the detergent-induced increase in ouabain-sensitive (Na+, K+)-ATPase activity, ATP-dependent ouabain binding, and lactate dehydrogenase activity (sarcoplasmic enzyme trapped in the TT vesicles). Sidedness of the sealed vesicles, estimated from latency of 5'-nucleotidase, acetylcholinesterase, and adenylate cyclase, was predominantly right-side out (69-76%, chicken TT and 62-70%, rabbit TT). In both chicken and rabbit native vesicles, high Mg(2+)-ATPase activity was detected by addition of ATP to the extravesicular medium; this activity was increased 14-12% by alamethicin pointing to the external localization of the active site. Furthermore, the enzymatic activity resulted partially inhibited by treatment of the chicken TT vesicles with proteinase K or p-hydroxymercuribenzoate. Concanavalin A stimulated 4-fold the chicken TT Mg(2+)-ATPase activity, an effect not potentiated by detergent permeabilization of the intact vesicles, indicating that lectin-binding sites were also solvent accessible. This stimulatory effect was not observed in native or permeabilized rabbit TT vesicles. From these results we conclude that the TT Mg(2+)-ATPase is an ectoenzyme with its nucleotide-hydrolyzing site and glycosylated regions facing the extracellular space. Inhibitors of ion-motive ATPases did not modify the enzyme activity, suggesting a different physiological role for the TT Mg(2+)-ATPase which may be involved in the regulation of muscle fiber functions affected by extracellular ATP levels.
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PMID:Transverse tubule Mg(2+)-ATPase of skeletal muscle. Evidence for extracellular orientation of the chicken and rabbit enzymes. 166 Apr 76

Effect of protein deficient diet on hepatic plasma membrane fluidity has been studied in rats using (i) steady state fluorescence polarization and anisotropy, (ii) phospholipid and cholesterol contents, (iii) phospholipid fatty acid composition, (iv) turnover of phosphatidyl choline (PC), and (v) activities of membrane-bound enzymes as parameters and rats fed casein (20%) diet as standard group. A significant increase in steady state fluorescence and anisotropy values was registered in the deficient group, indicating increased resistance and hence decrease in fluidity of the plasma membrane. Supplementation of the diet with lysine and threonine improved these values, thereby suggesting the significance of diet for membrane fluidity. Simultaneous significant alterations in other parameters, viz. (i) decrease in PC, PE and free cholesterol and increase in esterified cholesterol contents, (ii) decrease in unsaturation of fatty acids of PC, (iii) decrease in incorporation of NaH2 32PO4, [CH3-14C]choline and [CH3-14C]methionine into plasma membrane PC, and (iv) decrease in activities of plasma membrane 5'-nucleotidase and phosphodiesterase along with increase of (Na(+)-K+)ATPase and adenyl cyclase, were observed in the deficient group which on supplementation with lysine and threonine showed improvement over alterations.
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PMID:Hepatic plasma membrane fluidity and dietary proteins. 175 32

The effects of castration on fat cell plasma membrane structure and enzyme activities (adenylate cyclase and 5'-nucleotidase) were studied in pig adipose tissues in two fat deposits (subcutaneous and perirenal). Castration induced a fat cell enlargement in both tissues. Membrane cholesterol content was reduced and fluidity was increased in perirenal fat from castrated animals. Castration had no effect on 5'-nucleotidase activity which was higher in subcutaneous than in perirenal in both kinds of animals. Adenylate cyclase activity was studied in the presence of different effectors: isoproterenol-stimulations of the enzyme were not affected by castration but were site-specific. GppNHp-stimulated activities were increased in subcutaneous fat from castrated animals. Castration had no influence on forskolin stimulations. The magnitude of GppNHp- and forskolin-stimulated activities were found to be tissue-dependent. Membrane results are discussed in relation with castration-induced fat cell enlargement.
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PMID:Effect of castration and anatomical site on the plasma membrane structure and the activities of adenylate cyclase and 5'-nucleotidase in pig adipocytes. 181 62

The two clinically important classes of antimycotic drugs, the polyenes and azoles, act on the plasma membrane of the cell. The primary modes of action are believed to be through interaction with sterols (polyenes) and alteration in sterol composition of the membrane (azoles). In this report we show that, at growth inhibitory concentrations, the polyenes (nystatin and amphotericin) and azoles (miconazole and ketoconazole) also inhibit plasma membrane enzymes. There was extensive (greater than 75%) inhibition of the Candida albicans plasma membrane enzymes ATPase, glucan synthase, adenyl cyclase and 5'-nucleotidase, when assayed in situ. The antifungals papulacandin and echinocandin, which inhibit glucan synthesis, also inhibited plasma membrane enzymes in situ; glucan synthase (greater than 90%), 5'-nucleotidase (greater than 80%) and ATPase (70-80%). Purified plasma membrane was prepared from yeast cells of C. albicans by two different techniques: concanavalin A stabilization and coating of spheroplasts with silica microbeads. In the purified plasma membrane vesicles prepared from concanavalin A the adenyl cyclase and phosphodiesterase were extensively (greater than 90%) inhibited by the three different classes of antifungal drugs; variable inhibition was observed with ATPase (70-100%). The 3',5'-cyclic phosphodiesterase of the plasma membrane purified by the microbeads method was almost completely inhibited by all of the antifungals tested and there was partial inhibition of ATPase (20-85%) and adenyl cyclase (30-90%).
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PMID:The effects of azole and polyene antifungals on the plasma membrane enzymes of Candida albicans. 283 Mar 94

In cultured cells derived from isolated micromeres of sea urchin eggs, H+,K+-ATPase activity, which became detectable simultaneously with the initiation of spicule formation, was localized in the plasma membrane and the microsome fractions. Activities of marker enzymes for plasma membrane, 5'-nucleotidase, Na+,K+-ATPase, and adenylate cyclase, were found to be high in the plasma membrane fraction. Considerable activity of rotenone-insensitive NADPH-cytochrome c reductase, a marker enzyme for microsome, was detectable in the microsome fraction. These fractions exhibited barely any appreciable activity of markers for the other organellae. H+,K+-ATPase in plasma membrane probably mediates H+ release from the cells, in which H+ is produced in overall reaction to form CaCO3, the main component of spicules, from Ca2+, CO2 and H2O. Cl-,HCO3(-)-ATPase activity was also found in these two fractions before and after the initiation of spicule formation. After initiation, the skeletal vacuole fraction was obtained from subcellular structures containing spicules. Considerable activity of Cl-,HCO3(-)-ATPase was observed in this fraction, which exhibited a weak activity of UDP-galactose: N-acetylglucosamine galactosyltransferase, a marker enzyme for Golgi body. Cl-,HCO3(-)-ATPase in the skeletal vacuole membrane probably mediates HCO3- transport into the vacuoles to supply HCO3- for spicule formation.
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PMID:Distributions of H+,K+-ATPase and Cl-,HCO3(-)-ATPase in micromere-derived cells of sea urchin embryos. 283 20

1. We performed an enzymatic characterization of two different fractionation procedures of ventricles from rat hearts. The enzymatic assays covered succinic dehydrogenase as a marker for inner mitochondrial membranes, monoamine oxidase as a marker for outer mitochondrial membranes, NADPH-cytochrome c reductase and RNA as endoplasmatic reticular markers, acid phosphatase as a lysosomal marker, and lactic dehydrogenase as a marker for the "soluble" compartment; DNA was estimated for nuclear contamination. 2. The plasma membrane markers 5'-nucleotidase, Ca2+-ATPase, Mg2+-ATPase, Na+-K+-ATPase, and adenylate cyclase were determined. 3. The roughly prepared membrane fractions showed increased yields of the membrane markers; the number of beta receptors, determined with (-)-[3H] dihydroalprenolol and DL-propranolol, amounted to 68 +/- 6 fmol/mg protein (KD = 3390 +/- 450 pmol, Hill coefficient = 1.5). 4. The membrane fraction prepared with a linear sucrose gradient showed an increased inner mitochondrial membrane marker; presumably the outer mitochondrial membrane was stripped off. The beta-receptor number was 39 +/- 3 fmol/mg protein (KD = 6250 +/- 300 pmol; Hill coefficient = 1.2).
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PMID:Beta-adrenergic receptors and enzymes in rat myocardial membranes: implications of fractionation procedures and beta-adrenoceptor antagonists. 284 52

Cyclic AMP has been implicated as a regulator of capacitation, but the control of its metabolism in sperm remains obscure. A recent study of mouse sperm has shown capacitation-related changes in the activities of both adenylate cyclase, which increased during incubation, and cyclic nucleotide phosphodiesterase, which decreased. The present study was conducted to extend these observations by measuring phosphodiesterase activity in sperm incubated in media with modified calcium and/or glucose content, conditions known to modulate fertilizing ability. Phosphodiesterase activity of sequential sperm samples, taken first when sperm are essentially uncapacitated and then when they are either partially or completely capacitated, decreased with time under all conditions, and in each case the greater fall in activity was seen in the medium that would support the greater change in fertilizing ability of the sperm population. Sperm washed by centrifugation to remove epididymal fluid also displayed a reduction in phosphodiesterase activity with time. The medium surrounding the sperm contained about half of the total phosphodiesterase activity, as well as 5'-nucleotidase and adenosine deaminase. The crude enzyme preparation showed complex kinetic behavior when assayed over a range of cAMP concentrations, but the reduction in activity with time was seen at all substrate levels. The observed changes in phosphodiesterase activity, together with the increased adenylate cyclase activity seen under these sperm incubation conditions, would increase cAMP availability with time, thus providing further evidence for a fundamental role for cAMP in controlling the events of capacitation.
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PMID:Phosphodiesterase activity of mouse sperm incubated under conditions that modulate fertilizing potential in vitro. 285 27


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