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)

The compound N-[2-hydroxy-3-(1-naphthoxy)-propyl]-N'-bromoacetylethylenediamine (NHNP-NBE) was found to label covalently the beta-adrenergic receptor in turkey erythrocytes. The compound inhibits irreversibly 1-epinephrine-dependent adenylate cyclase activity [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] in the whole turkey erythrocyte as well as in the erythrocyte membranes possessing the beta-receptor. The affinity label blocks, also irreversibly, the specific [3H] propranolol binding, whereas other bromoacetyl compounds tested have no effect on binding, even at high concentrations, which cause enzyme inactivation. 1-Epinephrine and propranolol offer protection against the affinity label in whole turkey erythrocytes as well as in membranes prepared from these cells. The potential usefulness of an irreversible beta-antagonist is discussed.
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PMID:Affinity label for beta-adrenergic receptor in turkey erythrocytes. 18 May 28

Isoproterenol, corticotropin (ACTH), and triodothyronine immobilized on glass and Sepharose beads by diazotization procedures have been shown to interact with cultured tumor cells of "target tissue" origin. Cells used were rat glioma cells (C6), rat adrenal tumor cells (Y-1), and rat pituitary tumor cells (GH3). The rat glioma cells bound principally to immobilized isoproterenol, whereas the rat adrenal tumor cells bound to immobilized corticotropin, and rat pituitary tumor cells bound to immobilized triiodothyronine. Binding was inhibited by preincubation of the cells in soluble drug or hormone. With C6 cells there was a positive correlation between adenylate cyclase [ATP pyrophosphate-lyase (cyclizing, EC 4.6.1.1] stimulation and the degree of binding to the immobilized isoproterenol. Norepinephrine, bound through the ethanolamine side chain via an amide linkage, did not bind cells, demonstrating specific structural requirements for drug-cell interactions. HeLa cells were shown to bind tightly to diphtheria toxin coupled to Sepharose beads via an amide bond. This binding was inhibited by prior incubation of the Sepharose toxin with purified antitoxin. Toxin bound to Sepharose via an azo bond did not bind cells. These data suggest that the cell affinities are due to cell surface receptors interacting with the immobilized drugs and hormones, and that the observed affinities possibly reflect the relative receptor complement of these cells.
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PMID:Affinity isolation of cultured tumor cells by means of drugs and hormones covalently bound to glass and Sepharose beads. 18 May 34

Depending on growth conditions, the adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels of the fr mutant, a morphologically aberrant strain of Neurospora crassa, are reduced 2- to 5-fold. By taking advantage of the differences in phenotype of fr in liquid and agar cultures and the positive response of fr grown on solid support to exogenous theophylline, a relationship between the degree of morphological abnormality and intracellular cyclic AMP levels of the mutant is observed. Progressive restoration of the fr phenotype toward a normal state is paralleled by increases in cyclic nucleotide content. Striking differences in the sedimentation and thermal characteristics of the fr and wild-type adenylate cyclases [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] are observed. Approximately 50% of the normal activity sediments at 105,000 X g compared to 5% of the mutant enzyme. In addition, the overall stability of the fr adenylate cyclase is significantly decreased and its rate of inactivation at 37 degrees in the absence of substrate is 10-fold greater than the wild-type adenylate cyclase. Arrhenius plots also indicated that the Q10 (increase in rate per 10 degrees temperature increase) and the temperature of maximal activity of the fr enzyme are reduced. Supplementation of fr agar cultures with linolenic acid results in an elevated cyclic AMP content and a wild-type-like morphology similar to that obtained with inhibitors of phosphodiesterase (3':5'-cyclic AMP 5'-nucleotidohydrolase, EC 3.1.4.17). An increased thermostability of the fr adenylate cyclase occurs on linolenate enrichment of the mutant. It is concluded that the cyclic AMP deficiency is at least partially responsible for the fr phenotype and that this reduction results from a membrane defect that affects adenylate cyclase function.
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PMID:Adenosine 3':5'-cyclic monophosphate deficiency in Neurospora crassa. 18 53

1. Physiological concentrations of antidiuretic hormone increase diffusional water permeability but not measurable cyclic AMP content in the isolated papilla of the rat's kidney. 2. Theophylline (6 mM) increases diffusional water permeability and cyclic AMP content in the isolated papilla of the rat's kidney. 3. The increase in water permeability is detected with 5 muunits.ml-1 of ADH and is maximal with 50 muunits.ml-1. The same maximum was achieved with 6 mM theophylline. 4. Cyclic AMP and dibutyryl cyclic AMP both increase water permeability, but to a lesser extent than theophylline or ADH. 5. In the presence of theophylline, ADH causes a dose related generation of tissue cyclic AMP up to a dose of 2,000,000 muunits.ml-1. 6. Adenyl cyclase is increasingly activated by ADH up to doses of 2,000,000 muunits.ml-1. 7. These results suggest that while ADH activates the adenyl cyclase system and changes water permeability there are sufficient disparities to cast doubt on an exclusive role for cyclic AMP as the second messenger.
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PMID:The interrelationships between antidiuretic hormone, adenyl cyclase, tissue cyclic AMP and diffusional water permeability. 18 92

Membranes of rat caudate nucleus contain a dopamine-dependent adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] and a Ca++ binding protein that activates phosphodiesterase (3':5'-cyclic-AMP 5'-nucleotidohydrolase, EC 3.1.4.17). This activator can be released from the membranes by a phosphorylation with a 3':5' cAMP-dependent protein kinase (ATP-protein phosphotransferase, EC 2.7.1.37). Under the conditions of membrane phosphorylation and activator release, dopamine fails to activate striatal adenylate cyclase. The basal activity of this enzyme is not decreased by the release of the protein activator but the activation by NaF is reduced. Adenylate cyclase is not phosphorylated when the dopamine activation is blocked after the release of the activator, but other membrane proteins are phosphorylated. It is postulated that the endogenous protein stored in striatal membranes can regulate the intracellular concentration of cAMP by an activation of adenylate cyclase while stored in striatal membrane, and by an activation of phosphodiesterase when released into the cytosol after membrane phosphorylation.
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PMID:Regulation of dopamine stimulation of striatal adenylate cyclase by an endogenous Ca++ -binding protein. 18 77

The phosphodiesterase (3':5'-cyclic AMP 5'-nucleotidohydrolase, EC 3.1.4.17) inhibitor thepohylline enhances both the amplitude and duration of a long-lasting synaptic hyperpolarization in identified neuron R15 in Aplysia californica. Intraneuronal injection into R15 of glanylyl-imidodiphosphate, an adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activator, results in a deep and long-lasting hyperpolarization of the cell, similar to that produced by synaptic stimulation. Biochemical analysis confirms that guanylyl-imidodiphosphate activates adenylate cyclase in Aplysia californica nervous tissue, without affecting phosphodiesterase activity. These observations suggest that adenosine 3':5'-cyclic monophosphate plays a role in long-lasting synaptic inhibition and are consistent with a post-synaptic site of action for adenosine 3':5'-cyclic monophosphate.
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PMID:Intraneuronal guanylyl-imidodiphosphate injection mimics long-term synaptic hyperpolarization in Aplysia. 18 52

HeLa cells contain beta-adrenergic receptors that are characterized by specific binding of I[3H]dihydroalprenolol, increased 3':5'-cyclic AMP production in intact cells after incubation with l-isoproterenol, and increased adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity in the presence of l-isoproterenol. After cells were cultured with butyrate, the number of beta-adrenergic receptors, cyclic AMP production in intact cells, and adenylate cyclase activation by l-isoproterenol were increased severalfold over those of untreated cells. The increase involved the induction of synthesis of new receptor molecules with identical affinities for l-[3H]-dihydroalprenolol; all three processes were blocked by cycloheximide and actinomycin D. This induction was relatively specific for butyric acid and only the closely related short-chain fatty acids, propionic and valeric acids, were capable of partially inducing the same effect. In contrast to induction of beta-adrenergic binding sites, there was no increase in basal or fluoride-activated adenylate cyclase activity, indicating that the beta-adrenergic receptor and adenylate cyclase and different molecules that may be controlled separately.
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PMID:Induction of functional beta-adrenergic receptors in HeLa cells. 19 37

A modified version of an allosteric model for adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] previously analyzed for sustained oscillations of adenosine 3':5'-cyclic monophosphate (cAMP) in Dictyostelium discoideum [Goldbeter, A. (1975) Nature 253, 540-542] is examined to see whether it can account for the relay of cAMP pulses. Oscillations occur around a nonequilibrium, unstable stationary state when system parameters are in a certain domain. It is found that relay can occur outside this domain, in a restricted set of parameter values for which the solution ultimately tends to a stable steady state. A suprathreshold level of extracellular cAMP is needed to elicit relay which consists in a pulsatory synthesis of intracellular cAMP. Theoretical predictions are compared with the results of experiments on cAMP relay and oscillation in aggregation-competent cells of D. discoideum. The model suggests an explanation for the emergence of aggregation centers and for a sequence of developmental events observed in interphase amoebae.
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PMID:Unified mechanism for relay and oscillation of cyclic AMP in Dictyostelium discoideum. 19 5

Brief sonication of whole erythrocyte plasma membranes (ghosts) from toads at 4 degrees does not inactivate adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); EC 4.6.1.1] or destroy the receptor binding properties of hydroxybenzylpindolol or insulin. The hormonal (but not the fluoride-induced) stimulation of this enzyme is, however, lost. Fractionation of the small, resealed membrane fragments (vesicles) on discontinuous sucrose gradients results in the separation of vesicle populations differing grossly in size and protein composition. In addition, the distribution of the beta-adrenergic receptor, an insulin binding site, and adenylate cyclase among these vesicles fractions differs. The pattern of distribution of these functional structures can be altered differentially by manipulations of the ghosts before sonication. For example, brief preincubation with isoproterenol leads to a change in the relative distribution of beta-receptor (but not adenylate cyclase) among the various vesicle fractions; this effect is not obtained with beta-receptor antagonists, which block the isoproterenol effect. Exposure of the ghosts to different temperatures, changes in the divalent cation composition of the medium, or the addition of ATP also leads to changes in the distribution of surface markers of the subsequently formed vesicles. The results indicate gross asymmetries in the distribution of protein components within the plane of the membrane and raise important questions regarding the manner whereby functionally related and coupled components, such as hormone receptors and adenylate cyclase, interact.
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PMID:Topographic separation of adenylate cyclase and hormone receptors in the plasma membrane of toad erythrocyte ghosts. 19 22

Treatment of turkey erthrocyte membranes with cholera toxin caused an enhancement of the basal and catecholamine-stimulated adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activities. Both of these activities required the presence of GTP. The toxin effect on the adenylate cyclase activity concided with an inhibition of the catecholamine-stimulated guanosinetriphosphatase activity. Inhibition of the guanosinetriphosphatase, as well as enhancement of the adenylate cyclase activity, showed the same dependence on cholera toxin concentrations, and the effect of the toxin on both activities was dependent on the presence of NAD. It is proposed that continuous GTP hydrolysis at the regulatory guanyl nucleotide site is an essential turn-off mechanism, terminating activation of the adenylate cyclase. Cholera toxin inhibits the turn-off guanosinetriphosphatase reaction and thereby causes activation of the adenylate cyclase. According to this mechanism GTP should activate the toxin-treated preparation of adenylate cyclase, as does the hydrolysis-resistant analog guanosine 5'-(beta,gamma-immino)triphosphate [Gpp(NH)p]. Indeed, the toxin-treated adenylate cyclase was maximally activated, in the presence of isoproternol, by either GTP or Gpp(NH)p, while adenylate cyclase not treated with toxin was stimulated by hormone plus GTP to only one-fifth of the activity achieved with hormone plus Gpp(NH)p. Furthermore, the toxin-treated adenylate cyclase activated by isoproterenol plus GTP remained active for and extended period (half-time of 3 min) upon subsequent addition of the beta-adrenergic blocker, propranolol. The native enzyme, however, was refractory to propranolol only if activated by Gpp(NH)p but not by GTP.
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PMID:Mechanism of adenylate cyclase activation by cholera toxin: inhibition of GTP hydrolysis at the regulatory site. 19 81


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