Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study was made of the effects of various agents on adenylate cyclase in synaptosomes in both the absence and presence of the boiled supernatant from rat cerebral cortex. The activity of adenylate cyclase in these preparations was inhibited by the sulfhydryl reactive agent p-chloromercuribenzoate. Sulfhydryl compounds such cysteine, glutathione and Coenzyme A stimulated the enzymic activity in both the absence and presence of the boiled supernatant. The chelating agent 1.2-bis-(2-dicarboxymethylaminoethoxy)ethane caused a stimulation of the enzymic activity with and without the presence of the boiled supernatant. Adenine nucleotide (adenine, adenosine, AMP and ADP), GTP, Pi and carbamylcholine seemed to have little effect. The stimulatory substance in the boiled supernatant was estimated to have a molecular weight in the range of 1,000-1,300.
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PMID:Effects of various agents on synaptosomal adenylate cyclase activity in the absence and presence of the boiled supernatant. 18 Mar 22

The action of stimulants and imitators of the adenylate cyclase function (novodrin, sodium fluoride, cAMP), imitators of the guanylcyclase function (cGMP), inhibitors of adenylate cyclase (propranolol), izanylate cyclase (atropin) or phosphodiesterase (euphyllin, papaverin) on the body acetylating capacity measured from acetyl-PABA release, and CoA content in the liver was studied in experiments on male rats. The substances that mainly produce an increase in cAMP in the tissues augment the CoA endogenic pool and, as a rule, stimulate the acetylating capacity of the body. As compared to cAMP, the eczogenic cGMP raises, but to a significantly less measure, the CoA content and does not change the rate of arylamine acetylation. Paraverin is an exception to the rule since it seems to exert a direct action on the enzymatic system of acetylation. When administered to rats cGMP elicits a cAMP-like but a weaker action on the CoA pool. It is suggested that combined use of test substances prolonging cAMP effects and drugs belonging to a group of arylamines is not advisable because of active inactivation of the latter compounds.
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PMID:[Effect of preparations that alter the cyclic nucleotide level on acetylation processes]. 22 98

The properties of the beta-adrenergic receptor which regulates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing)8 EC 4.6.1.1] in the pineal gland are similar to the properties of the sites which specifically bind l-[3H]alprenolol, a potent beta-adrenergic antagonist. Stimulation of the beta-adrenergic receptor results in a 30-fold increase in the activity of N-acetyltransferase (= arylamine acetyltransferase; acetyl CoA:arylamine N-acetyltransferase, EC 2.3.1.5), an enzyme involved in the synthesis of thepineal hormone melatonin. In the normal diurnal light-dark cycle there is greater physiological stimulation of the beta-adrenergic receptor in the pineal during the night than during the day. Pineals from rats kept in constant light for 24 hr possess more hormone-sensitive adenylate cyclase and specifically bind more l-[3H]alprenolol than do pineals from rats kept in the dark overnight. When rats, exposed to light for 24 hr, are treated with the beat-adrenergic agonist isoproterenol, there is a rapid loss of both hormone-sensitive adenylate cyclase activity and specific l-[3H]alprenolol binding sites. There is no change in the affinity of adenylate cyclase for isoproterenol or for its substrate, ATP. Similarly, although there are fewer binding sites, there is no change in the affinity of the remaining sites for either agonist or antagonist. Inhibition of protein synthesis with cycloheximide does not affect the loss of either adenylate cyclase activity or specific binding sites. The data suggest that stimulation of the beta-adrenergic receptor causes a rapid decrease in the number of available receptors and in hormone-sensitive adenylate cyclase activity; conversely, lack of stimulation causes an increase in these parameters. It is suggested that these changes contribute to the phenomena of super- and subsensitivity in the pineal gland by regulating the capacity of the pineal to synthesize cyclic AMP in response to beta-adrenergic stimulation.
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PMID:Rapid changes in rat pineal beta-adrenergic receptor: alterations in l-(3H)alprenolol binding and adenylate cyclase. 105 61

Haemolysin secreted by pathogenic Escherichia coli binds to mammalian cell membranes, disrupting cellular activities and lysing cells by pore-formation. It is synthesized as nontoxic prohaemolysin (proHlyA), which is activated intracellularly by a mechanism dependent on the cosynthesized HlyC. Haemolysin is one of a family of membrane-targeted toxins, including the leukotoxins of Pasteurella and Actinobacillus and the bifunctional adenylate cyclase haemolysin of Bordetella pertussis, which require this protoxin activation 1-5. HlyC alone cannot activate proHlyA, but requires a cytosolic activating factor6. Here we report the cytosolic activating factor is identical to the acyl carrier protein and that activation to mature toxin is achieved by the transfer of a fatty acyl group from acyl carrier protein to proHlyA. Only acyl carrier protein, not acyl-CoA, can promote HlyC-directed proHlyA acylation, but a range of acyl groups are effective.
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PMID:Activation of Escherichia coli prohaemolysin to the mature toxin by acyl carrier protein-dependent fatty acylation. 206 68

1. Short-term effects of lipolytic agents in the absence or in the presence of insulin on fatty acid biosynthesis have been examined, in terms of the control rate of [1-14C]acetate incorporation into labeled fatty acids in the presence of glucose, as stimulator of lipogenesis by generating NADPH for the process. 2. The relationship between lipogenesis and lipolysis in the absence or in the presence of insulin was compared with a variety of adenylate cyclase activators. 3. The data obtained reveal that a reciprocal relationship exists between lipogenesis and lipolysis. 4. The changes in the activity of hexose monophosphate shunt produced by activation or inhibition of lipogenic process has been studied. 5. The regulation of the hexose monophosphate shunt activity mainly by the intracellular fatty acyl-CoA concentration and NADPH/NADP ratio is discussed.
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PMID:Metabolic antagonism between insulin action and activators of adenylate cyclase in rat fat cells. 244 76

Profound alterations in the microsomal fatty acyl-CoA desaturase activities and cyclic AMP production of a unicellular eukaryote, Tetrahymena pyriformis NT-1, originally grown in the glucose-deficient medium, were observed, following the administration of glucose or beta-adrenergic agonists such as epinephrine and isoproterenol. There was a great increase of stearoyl-CoA (delta 8) desaturase activity coincident with a 2-fold decrease of oleoyl-CoA (delta 12) desaturase activity over the first 2 h after administration of these compounds. During this period of time, it was found that the production in vivo of labeled oleic acid from [14C]acetic or [3H]palmitic acid increases 2-fold and the formation in vivo of each labeled linoleic and gamma-linolenic acids drastically decreases. Glucose or beta-adrenergic agonists caused an increase of stearoyl-CoA-stimulated reoxidation rate of NADH-reduced cytochrome b5 but depressed oleoyl-CoA-stimulated reoxidation rate of b5, indicating that both desaturase activities are controlled by the respective terminal components of the desaturase system. A significant and reproducible increase of adenylate cyclase activity and a slight decrease of cyclic AMP phosphodiesterase activity were observed to occur within the first 2 h after the addition of these compounds, when cyclic AMP content in Tetrahymena cell rose by 3-4-fold. Propranolol, a beta-adrenergic blocker, abolished the effects of glucose or beta-adrenergic agonists on the activities of fatty acyl-CoA desaturases and the terminal components as well as cyclic AMP production of cells. These results suggest that glucose and beta-adrenergic agonists may modulate the microsomal fatty acyl-CoA desaturase system in Tetrahymena by acting through the increase of intracellular cyclic AMP content.
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PMID:A possible cyclic AMP-mediated regulation of microsomal fatty acyl-CoA desaturation system in Tetrahymena microsomes. 286 55

The relationship between Fc receptor specific for IgG2b (Fc gamma 2bR) and membrane adenylate cyclase was investigated. The specific binding of IgG2b immune complexes to P388D1 cell surface Fc gamma 2bR was found to inhibit the basal, forskolin-stimulated, and NaF-stimulated activities of membrane adenylate cyclase by 53%, 57%, and 31%, respectively. On the other hand, the binding of IgG2a immune complexes to cell surface Fc gamma 2aR increased the basal activity about 2.5-fold and the forskolin- and NaF-stimulated activities slightly. The fusion of liposomes containing Fc gamma 2bR, which was obtained as phosphatidylcholine (PC) binding protein as previously described, with the cyc- membrane preparations resulted in the marked suppression of membrane adenylate cyclase, whereas the fusion of liposomes containing Fc gamma 2a, which was obtained as IgG-binding protein, led to about a 2.7-fold increase. The Fc gamma 2bR-mediated inhibition of adenylate cyclase may be due to the temporary change of the lipid environment caused by the action of phospholipase A2, which was previously shown to be associated with Fc gamma 2bR, since (1) addition of snake venom phospholipase A2 or cholate-solubilized PC-binding protein to P388D1 membrane was found to inhibit adenylate cyclase in a dose-dependent manner, (2) prior treatment of snake venom phospholipase A2 or PC-binding protein with a specific inhibitor, p-bromophenacyl bromide, significantly reduced their inhibitory action, and (3) a product of phospholipase A2 action, arachidonic acid, was found to be an effective inhibitor of membrane adenylate cyclase, whereas the other product, lysophosphatidylcholine, was much less inhibitory than arachidonic acid. Arachidonic acid appeared to interfere with the functions of both guanine nucleotide-binding stimulatory (Gs) protein and the catalytic subunit of adenylate cyclase, since exogenously added arachidonic acid significantly suppressed the GTPase activity of P388D1 membrane and the forskolin response of the adenylate cyclase activity of Gs protein deficient cyc- membrane. The primary site of action of lysophosphatidylcholine is not clear but may be other than Gs protein and/or the catalytic subunit, since it did not change either GTPase activity of P388D1 membrane or the response to forskolin of adenylate cyclase of cyc- membrane. The Fc gamma 2bR/phospholipase A2 mediated inhibition of adenylate cyclase would be a transient event in viable cells, since phospholipase A2 did not inhibit adenylate cyclase in the presence of microsomal fraction, mitochondria, and coenzyme A, suggesting the occurrence of rapid acylation of CoA and reacylation of lysolecithin.
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PMID:Relationship between Fc gamma 2b receptor and adenylate cyclase of a murine macrophagelike cell line, P388D1. 295 16

Incubation of rat liver plasma membranes with insulin enhances the production of small molecular weight substances which regulate the activity of liver acetyl CoA carboxylase. While low concentrations of insulin cause the release of a carboxylase stimulator from membranes, concentrations greater than 10(-9) M generate less stimulating activity. This biphasic concentration curve for insulin can be resolved by differential alcohol extraction into two fractions which have antagonistic activity. The production of both substances is enhanced by insulin. Chemical and chromatographic evidence suggest that these substances are identical to the previously described "mediators" which regulate both pyruvate dehydrogenase and adenylate cyclase activities.
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PMID:Putative mediators of insulin action regulate hepatic acetyl CoA carboxylase activity. 613 1

Plasma membrane phospholipids were modified by incubation in the presence of linoleyl-CoA with or without added lysolecithin (LPC) for various length of time. In the absence of LPC, a maximum of 10 nmoles linoleyl-phosphatidylcholine (PC) were synthesized and the ATPase specific activities were not affected whereas in the presence of LPC, when linoleyl-PC synthesis rose from 10 to 80 nmoles, the ATPase activities were decreased. The decrease was similar in the Na,K- or in the Mg-dependent-ATPase and reached maximally 30-40%. LPC by itself did not modify the ATPases. A concomitant decrease in DPH polarization was observed when linoleate was incorporated into phospholipids. We concluded that the decreased ATPase specific activities may be due to an increased fluidity of membranes produced by linoleyl- PC synthesis. We compare this modulation of ATPases by the membrane fluidity with the specific effect of linoleyl- PC species on adenylate cyclase.
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PMID:Linoleate incorporation into rat liver membranes phospholipids: effect on plasma membrane ATPase activities and physical properties. 623 79

Methyl lidocaine is an experimental anti-arrhythmic drug which has been shown to enhance the biosynthesis of phosphatidyl-inositol (PI) in the hamster heart. In this study, the effect of methyl lidocaine on enzymes involved in the biosynthesis of PI in the heart was examined. When the hamster heart was perfused with labelled methyl lidocaine, the majority of the compound was not metabolized after perfusion. The direct action of methyl lidocaine on an enzyme was studied by the presence of the drug in enzyme assays, whereas its indirect action was studied by assaying the enzyme activity in the heart after methyl lidocaine perfusion. CTP:phosphatidic acid cytidylyl-transferase, a rate-limiting enzyme in PI biosynthesis, was stimulated by methyl lidocaine in a direct manner. Kinetic studies revealed that methyl lidocaine caused a change in the affinity between the enzyme and phosphatidic acid and resulted in the enhancement of the reaction. Alternatively, acyl-CoA:lysophosphatidic acid acyltransferase, another key enzyme for PI biosynthesis, was not activated by the presence of methyl lidocaine. However, the enzyme activity was stimulated in hearts perfused with methyl lidocaine. The enhancement of the acyl-transferase by methyl lidocaine perfusion was found to be mediated via the adenylate cyclase cascade with the elevation of the cyclic AMP level. The stimulation of protein kinase A activity by cyclic AMP resulted in the phosphorylation and activation of the acyltransferase. Interestingly, the activity of protein kinase C was not stimulated by methyl lidocaine perfusion. We conclude that the enhancement of PI biosynthesis by methyl lidocaine in the hamster heart resulted from the direct activation of the cytidylyltransferase, as well as the phosphorylation and subsequent activation of the acyltransferase.
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PMID:The modulation of phosphatidylinositol biosynthesis in hamster hearts by methyl lidocaine. 763 4


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