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 existence of an invasive adenylate cyclase in dialyzed urea extracts of the bacterium Bordetella pertussis has been suggested recently. Gel filtration of B. pertussis dialyzed urea extract shows that the invasive enzyme constitutes only a small portion of the total adenylate cyclase activity found in the extract. Its size is different than the size of the two peaks of adenylate cyclase activity identified in the extract. Ca2+ is absolutely required for the penetration of the invasive enzyme, it also controls the rate of intracellular cAMP accumulation in human lymphocytes exposed to dialyzed extract. These characteristics may be attributed to the increase in the size of the invasive enzyme as found by gel filtration chromatography of the extract in the absence of Ca2+. Removal of nonpenetrating adenylate cyclase that adheres to lymphocytes permits a direct assay of the intracellular enzyme. The time course of intracellular accumulation of adenylate cyclase activity is similar to the time course of intracellular accumulation of cAMP, suggesting that the invasive enzyme is rapidly deactivated, but not degraded, since it can be detected upon cell disruption. No appreciable amount of the enzyme is introduced when cells are incubated with extract at 4 degrees C for 120 min, then washed and incubated further at 37 degrees C. Concanavalin A inhibits cAMP accumulation irrespective of the time of its addition, and EGTA prevents penetration of the invasive enzyme even if added 20 min after addition of extract. These findings are different from those observed in other bacterial toxins thought to be internalized by receptor-mediated endocytosis. However, the cellular penetration of B. pertussis adenylate cyclase is cell-selective. It does not occur in human erythrocytes. In addition to human lymphocytes, S49 cyc- murine lymphoma, turkey erythrocytes, and rat oocytes accumulate cAMP in response to B. pertussis extract.
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PMID:Bordetella pertussis invasive adenylate cyclase. Partial resolution and properties of its cellular penetration. 285 87

Growth of Bordetella pertussis in Stainer & Scholte medium in which the NaCl had been replaced by one of several inorganic or organic salts resulted in a large decrease in adenylate cyclase activity, histamine-sensitizing activity and in the amounts of two cell-envelope polypeptides of Mr 28000 and 30000. Although some variation between strains was observed, there was never a case where one of these properties was lost independently of the others. Cultures in which these properties were lost had decreased amounts of extracellular cAMP when compared to NaCl-grown cultures. Adenylate cyclase activity was detected in three locations of B. pertussis cultures (extracellular, extracytoplasmic but cell-associated, and cytoplasmic). After growth in medium containing high concentrations of MgSO4, enzyme activity was decreased to a similar extent in all three locations.
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PMID:The effect of growth conditions on adenylate cyclase activity and virulence-related properties of Bordetella pertussis. 285 46

During MgSO4-induced modulation of Bordetella pertussis, adenylate cyclase activity, histamine-sensitizing activity (HSA) and the major cell-envelope polypeptides with Mr 28000 and 30000 (X polypeptides) were lost synchronously at a rate which could be accounted for by a simple growth-dilution effect. MgSO4 and other compounds which induced the above phenotypic change caused little inhibition of adenylate cyclase activity. Nicotinic acid was the sole exception and at 4.1 mM-caused 60% inhibition of activity. Lysates of modulated cells, mixed with lysates of unmodulated cells, had no effect on either adenylate cyclase activity or HSA. Protein synthesis was a prerequisite for MgSO4-induced modulation and also for the reversal of this process. Exogenous cAMP and dibutyryl cAMP (5 mM) had no counteracting effect on MgSO4- or nicotinic acid-induced modulation. The concentration of MgSO4 required to induce loss of the X polypeptides (10 to 11 mM) was not altered by promoting adenylate cyclase activity by including an activator in the growth medium. In one culture containing 10 mM-MgSO4 and activator, partial loss of the X polypeptides occurred and yet the extracellular cAMP concentration was twice that of cultures without activator and where full expression of the X polypeptides occurred. [3H]cAMP-binding activity was detected in cell extracts of several strains of B. pertussis, but antiserum against purified Escherichia coli catabolite repressor protein gave no reaction with B. pertussis cell extracts. Respiration rates with amino acids were similar for modulated and unmodulated variants and an avirulent strain of B. pertussis. These results are discussed in relation to a possible causal role for adenylate cyclase in modulation of B. pertussis.
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PMID:Adenylate cyclase activity during phenotypic variation of Bordetella pertussis. 285 47

Eighteen strains of Bordetella bronchiseptica, selected on the basis of previously determined phenotypic characteristics, were examined for their ability to induce ciliostasis in canine tracheal outgrowth cultures. Fifteen strains grown on brucella agar caused ciliostasis. Strains that did not cause ciliostasis were stable, nonpiliated, and nonhemolytic, they did not produce extracellular adenylate cyclase, and were morphologically indistinguishable from rough-phase variants on brucella agar. Plasmids were detected in only five of the strains which induced ciliostasis, transfer of plasmids from four of these strains to one which did not induce ciliostasis did not alter its virulence or colony morphology. All strains which were hemolytic on Bordet-Gengou agar produced extracellular adenylate cyclase. Two nonhemolytic strains, one which produced only rough colonies on brucella agar, also induced ciliostasis. Two types of colony (phase) variation were observed: one recognizable on both brucella agar and Bordet-Gengou agar at frequencies of less than or equal to 10(-2), associated with multiple loss of virulence determinants, and the other recognizable only on Bordet-Gengou agar at frequencies of greater than or equal to 10(-2), associated with flagellum expression. The possession of readily detectable somatic pili was the only phenotypic characteristic consistently associated with the ability to induce ciliostasis. Formalin-killed and chloramphenicol-inhibited B. bronchiseptica strain 110H organisms had detectable pili and attached to cilia, but did not cause ciliostasis. Protease-treated B. bronchiseptica strain 110H organisms did not have detectable pili and in the presence of chloramphenicol did not attach to cilia. Attachment to cilia, although not in itself sufficient to cause ciliostasis, is intimately associated with and may be required for the induction of ciliostasis by B. bronchiseptica strains.
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PMID:Influence of potential virulence determinants on Bordetella bronchiseptica-induced ciliostasis. 286 15

Bordetella pertussis, the pathogen responsible for whooping cough, releases a soluble calmodulin-sensitive adenylate cyclase into its culture medium. Recently, Confer and Eaton [Confer, D., & Eaton, J. (1982) Science (Washington, D.C.) 217, 948-950], as well as Hanski and Farfel [Hanski, E., & Farfel, Z. (1985) J. Biol. Chem. 290, 5526-5536], have shown that crude extracts from B. pertussis containing adenylate cyclase activity cause elevations in intracellular cAMP when incubated with human neutrophils or lymphocytes. These investigators proposed that the bacterial enzyme enters animal cells and catalyzes the formation of cAMP from intracellular ATP. In this study, B. pertussis adenylate cyclase was purified to remove contaminating islet activating protein and examined for its effects on intracellular cAMP levels of human erythrocytes and N1E-115 mouse neuroblastoma cells. In both cases, the enzyme catalyzed the formation of intracellular cAMP. Addition of calmodulin to the adenylate cyclase preparations completely inhibited formation of intracellular cAMP catalyzed by the bacterial enzyme, indicating that cAMP was not synthesized extracellularly and then taken up by the cells. These experiments illustrate that the bacterial enzyme does enter animal cells and that the enzyme-calmodulin complex does not.
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PMID:Calmodulin inhibits entry of Bordetella pertussis adenylate cyclase into animal cells. 286 77

Bordetella pertussis, the bacterium responsible for whooping cough, releases a soluble, calmodulin-sensitive adenylate cyclase into its culture medium. B. pertussis mutants deficient in this enzyme are avirulent, indicating that the adenylate cyclase contributes to the pathogenesis of the disease. It has been proposed that B. pertussis adenylate cyclase may enter animal cells and increase intracellular adenosine cyclic 3',5'-phosphate (cAMP) levels. We have purified the enzyme extensively from culture medium using anion-exchange chromatography in the presence and absence of calmodulin and gel filtration chromatography. The enzyme was purified 1600-fold to a specific activity of 608 mumol of cAMP min-1 mg-1 and was free of islet activating protein. The molecular weight of the enzyme was 43 400 in the absence of calmodulin and 54 200 in the presence of calmodulin. The Km of the bacterial enzyme for adenosine 5'-triphosphate was 2.0 mM, whereas the Km of the calmodulin-sensitive adenylate cyclase from bovine brain was 0.07 mM. Although the enzyme was not purified to homogeneity, its turnover number of 27 000 min-1 is the highest documented for any adenylate cyclase preparation.
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PMID:Purification and characterization of a calmodulin-sensitive adenylate cyclase from Bordetella pertussis. 286 78

The extracellular adenylate cyclase of Bordetella pertussis was partially purified and found to contain high- and low-molecular-weight species. The high-molecular-weight form had a variable molecular weight with a peak at about 700,000. The smaller species had a molecular weight of 60 to 70,000 as determined by gel filtration. The low-molecular-weight form could be derived from the high-molecular-weight species. The high-molecular-weight complex purified from the cellular supernatant was highly stimulated by calmodulin, while the low-molecular-weight enzyme was much less stimulated. Active enzyme could be recovered from sodium dodecyl sulfate (SDS) gels at positions corresponding to molecular weights of about 50,000 and 65,000. Active low-molecular-weight enzyme recovered from SDS gels migrated with a molecular weight of about 50,000, which coincides with a coomassie blue-stained band. However, when both high- and low-molecular weight preparations were analyzed in 8 M urea isoelectrofocusing gels, the enzyme activity recovered did not comigrate with stained protein bands. The enzyme recovered from denaturing isoelectrofocusing or SDS gels was activated by calmodulin, indicating a direct interaction of calmodulin and enzyme. The high-molecular-weight form of the enzyme showed increasing activity with calmodulin concentrations ranging from 0.1 to 500 nM, while the low-molecular-weight form was fully activated by calmodulin at 20 nM. Adenylate cyclase on the surface of living cells was activated by calmodulin in a manner which resembled that found for the high-molecular-weight form.
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PMID:Secreted adenylate cyclase of Bordetella pertussis: calmodulin requirements and partial purification of two forms. 287 55

A number of virulence factors of Bordetella pertussis have been isolated and studied for their roles in pathogenesis and are under consideration, singly and in combinations, for inclusion in candidate acellular pertussis vaccines to be used in clinical trials to demonstrate safety and efficacy. Prospective immunogens would include lymphocytosis-promoting factor, agglutinogens, adenylate cyclase, filamentous haemagglutinin, heat-labile toxin and tracheal cytotoxin. Some of these factors are toxins and would need to be properly toxoided before being formulated into a vaccine. Clinical trials with acellular pertussis vaccines are planned or in progress in several countries.
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PMID:Prospects for a new acellular pertussis vaccine. 287 Jun 76

Calmodulin-activated, adenylate cyclase toxin, a virulence factor produced by the human respiratory pathogen Bordetella pertussis, elicits marked accumulation of cyclic AMP in cell lines from rat pituitary tumors. This effect is associated with and apparently responsible for an enhanced release of prolactin and/or growth hormone from GH3, GH4C1 and 235-1 cells. The utility of this novel toxin in probing cyclic AMP-mediated responses is supported by these observations and studies with pertussis and cholera toxins.
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PMID:Bacterial adenylate cyclase increases cyclic AMP and hormone release in pituitary tumor cells. 287 35

We have studied the effects of KUM 32 and CBS 1276, two clonidine-related drugs, upon the adenylate cyclase system of human platelets. Both drugs behaved as potent antagonists of epinephrine-induced platelet aggregation. [3H]Yohimbine binding studies revealed that the drugs bind to the alpha 2 adrenergic receptor of human platelets. KUM 32 and CBS 1276 also behaved as strong inhibitors of adenylate cyclase activity. This inhibition, which was not competitive with respect to ATP, is not an alpha 2 adrenergic phenomenon since it was not antagonized by yohimbine and was still observed in the absence of GTP. Moreover, pretreatment of platelet membranes with islet activating protein from Bordetella pertussis (IAP) had no effect on the inhibition by KUM 32, CBS 1276 and adenosine, although it completely reversed the effect of epinephrine and partially reversed the effect of clonidine. These results show that clonidine-like drugs may have different impacts on the adenylate cyclase system of human platelets. This system cannot be used as a pharmacological predictive test for alpha 2 adrenergic agonist activity, as various compounds, known to have central alpha 2 adrenergic agonist properties, do not behave as full agonists for the alpha 2 adrenergic receptor of human platelets.
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PMID:Critical assessment of the platelet adenylate cyclase system as a potential model for testing alpha 2 adrenergic activity. 287 41


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