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 beta-adrenergic agonist L-isoproterenol stimulated the enzymic synthesis of phosphatidyl-N-monomethylethanolamine and phosphatidylcholine in rat reticulocyte ghosts containing the methyl donor S-adenosyl-L-methionine. The stimulation was stereospecific, dose-dependent, and inhibited by the beta-adrenergic agonist propranolol. The addition of GTP inside the resealed ghosts shifted the dose-response of phospholipid methylation by L-isoproterenol to the left by 2 orders of magnitude. Direct stimulation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] with sodium fluoride or cholera toxin did not increase the methylation of phospholipids. At a concentration of S-adenosyl-L-methionine that stimulates synthesis of phosphatidyl-N-monomethylethanolamine, the activity of isoproterenol-sensitive adenylate cyclase was increased 2-fold without changes in the basal activity of adenylate cyclase and the number of beta-adrenergic receptors. The increase of phospholipid methylation by L-isoproterenol decreased membrane viscosity and increased translocation of methylated lipids. These findings indicate that enhancement of phospholipid methylation by L-isoproterenol decreases membrane microviscosity and thus increases lateral movement of the beta-adrenergic receptors and coupling with adenylate cyclase.
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PMID:beta-Adrenergic receptor agonists increase phospholipid methylation, membrane fluidity, and beta-adrenergic receptor-adenylate cyclase coupling. 3 51

Glucagon1-21 has been prepared by treating native glucagon with carboxypeptidase A. Purified glucagon1-21 did not contain detectable methionine (less than 0.001 residue/mol) and the activity of the compound did not change after treatment with cyanogen bromide as has been shown with native glucagon. Glucagon1-21 stimulates hepatic adenylate cyclase activity to the same extent as native glucagon but with 0.1% the potency. Glucagon1-21 also displayed 0.1% the binding affinity of native glucagon to the glucagon receptor in hepatic membranes. Glucagon22-29 alone or in combination with glucagon1-21 did not activate adenylate cyclase or displase 125I-glucagon from its receptor. The finding that glucagon1-21 is a full agonist on adenylate cyclase is discussed in relation to the structure-function relationships required for the biological action of glucagon.
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PMID:A reassessment of structure-function relationships in glucagon. Glucagon1-21 is a full agonist. 21 Jan 80

Addition of 0.1% casein hydrolysate to a minimal growth medium decreased membrane-bound transhydrogenase activity in Escherichia coli by about 80%. Of the amino acids added individually to the growth medium, only leucine and, to a lesser extent, methionine and alanine were effective, alpha-Ketoisocaproate- and leucine-containing peptides repressed the activity, and leucine also repressed activity in adenyl cyclase-deficient and relaxed strains. Derepression of transhydrogenase followed the removal of leucine from the growth medium and was sensitive to rifampin and chloramphenicol. A phosphoglucoisomerase-deficient strain that was forced to use the hexose monophosphate shunt exclusively had normal levels of transhydrogenase, which was repressed by leucine. Transhydrogenase activity doubled in mutants lacking either of the shunt dehydrogenases but was still repressed by leucine. In strains constitutive for the leucine biosynthetic operon, transhydrogenase was repressed by leucine but in strains livR and lst R, with leucine transport resistant to leucine repression, transhydrogenase was not repressed by leucine. These data suggest that transhydrogenase may have a function in the transport of branched-chain amino acids. In a hisT strain (which has altered leucyl-tRNA), transhydrogeanse was at a repressed level without the addition of leucine, suggesting that leucyl-tRNA may be involved in the regulation.
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PMID:Repression of Escherichia coli pyridine nucleotide transhydrogenase by leucine. 35 Aug 21

A technique is described for labeling bovine parathyroid hormone (bPTH) with tritium by [3Hmethyl exchange. The methionine residues were first methylated with [3H]methyl iodide at pH 4, and the reaction products were separated by cation exchange chromatography. The major peak consisted to hormone in which both methionines were converted to [3H]methyl methionine sulfonium iodide (3H-methylated bPTH). This product was then demethylated with 2-mercaptoethanol (6 M) at pH 8.6 to regenerate the hormone in an unmodified but tritiated form ([3H]bPTH), with a specific activity of 1.7 Ci/mmol. High pressure liquid chromatographic analysis showed that 96% of the radioactivity was incorporated into the methionine residues. There was no evidence of any alteration in the primary structure, as [3H]bPTH was found to run in the same position as unlabeled bPTH on cation exchange chromatography and disc gel electrophoresis and to have an identical absorption spectrum in the 240- to 330-nm range. Moreover, [3H]bPTH had full biological activity, as measured by an in vitro bioassay based on activation of rat renal cortical adenylate cyclase, although 3H-methylated bPTH was almost completely inactive. Similarly, while 3H-methylated bPTH had reduced potency in a RIA specific for antigenic sites in the 1--34 region of the sequence, [3H]bPTH was found to have full activity. The preparation of labeled bPTH was repeated using [14C]methyl iodide, with similar results, although [14C]bPTH was found to have somewhat reduced immunological and biological activities. While [3H]bPTH had a lower specific activity than can be obtained by various other techniques for incorporating tritium or 125I into peptides, biosynthetic labeling is at present the only alternative method for preparing biologically active, labeled bPTH without altering the primary structure. By comparison with this technique, the present method gave a product of a much higher specific activity which was labeled specifically in the biologically essential amino-terminal region. The same simple chemical procedures are clearly of wide potential application to the preparation of other labeled peptides.
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PMID:Studies of the biological and immunological properties of parathyroid hormone, labeled selectively on the methionine residues by [3H]methyl exchange to high specific activity. 47 96

Incubation of neuroblastoma X glioma hybrid cells for 12-97 hr with methionine-enkephalin results in an increase in adenylate cyclase activity [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] that is mediated by the opiate receptor. The results show that cells become tolerant to, and dependent upon, enkephalin.
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PMID:Tolerance and dependence evoked by an endogenous opiate peptide. 106 10

Application of FMRFamide (Phe-Met-Arg-Phe-NH2) induced a slow depolarization in neurons of the Aplysia abdominal ganglion. In voltage-clamped cells, FMRFamide induced a slow inward current that increased when the membrane was depolarized beyond -85 mV, showing a negative slope conductance. However, this inward current never reversed to outward current when hyperpolarized beyond the equilibrium potential for K+. The FMRFamide-induced response was markedly augmented in Ca(2+)-free media, but depressed in Na(+)-free media. It was unaffected by a change in external potassium. Intracellular injection of guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) significantly depressed the FMRFamide response in a dose-dependent way. Injection of cholera toxin (CTX) which did not cause any current response, selectively and irreversibly blocked the FMRFamide response. Neither 3'-deoxyadenosine, an inhibitor of adenylate cyclase, nor H-8, an inhibitor of cyclic adenosine 3',5'-monophosphate (cyclic AMP)-dependent kinase, depressed the FMRFamide response. 3-Isobutyl-1-methylxanthine (IBMX) did not augment the FMRFamide response appreciably. The FMRFamide response was not occluded at all by a relatively large injection of 8-bromo-cyclic AMP. It was concluded that the FMRFamide response is produced by the opening of the voltage-dependent Na(+)-channels via activation of a certain CTX-sensitive G-protein which is different from conventional "Gs" that activates adenylate cyclase.
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PMID:G-protein mediating the slow depolarization induced by FMRFamide in the ganglion cells of Aplysia. 128 79

Immunocytochemistry and a radioimmunoassay were used to investigate the existence and distributions of various regulatory peptide immunoreactivities (ir) in human submandibular and parotid glands. Numerous nerve fibers containing vasoactive intestinal polypeptide (VIP) and peptide histidine methionine (PHM), or neuropeptide tyrosine (NPY) and C-flanking peptide of NPY (CPON)-ir were found in close proximity to acini, ducts and blood vessels. Only a few calcitonin gene-related peptide (CGRP)- and substance P (SP)-ir nerve fibers could be demonstrated and were mainly localized around blood vessels and ducts. Galanin and the recently discovered peptides helospectin and pituitary adenylate cyclase activating peptide were unable to be detected in the salivary glands studied. Preliminary quantitative investigations of four human submandibular glands using radioimmunoassay showed that VIP-ir had the highest concentration, followed by NPY-ir and CGRP-ir; SP-concentrations were below the detection limit. The possible physiological significance of these peptides for salivary secretion is discussed.
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PMID:[Peptidergic innervation of human salivary glands (parotid gland and submandibular gland)]. 133 45

1. FMRFamide and the Catch relaxing peptide (CARP) at 0.01-0.1 nM modulate acetylcholine (ACh) induced currents of identified neurons of Helix aspersa, but have no direct effect on membrane current and conductivity. 2. Both FMRFamide and CARP noncompetitively inhibit ACh Cl- responses while having either no effect or increasing ACh Na+/K+ response. 3. The inhibitory effect of FMRFamide and CARP on the ACh Cl- response was eliminated following pretreatment with forskolin (20 microM), an activator of adenylate cyclase. 4. Ascaris peptide (ASC) and a synthetic CARP analogue NORL-CARP, in which the amino acid methionine is replaced by either leucine or norleucine, at 1-10 microM, showed no effect on responses to ACh. 5. FMRFamide and CARP, at 10 nM, increased cAMP levels to 240% and 148% respectively above resting basal cAMP levels, while ASC and NORL-CARP had no significant effective. 6. Our results suggest that FMRFamide and CARP, in low concentrations, modulate ACh responses of Helix neurons, possibly through changes in cAMP levels. They also indicate the importance of the presence of methionine in these neuroactive peptides.
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PMID:Low concentrations of neuroactive peptides modulate cholinergic transmission and cyclic AMP levels in Helix aspersa. 133 59

We recently demonstrated the synthesis and secretion of an atriopeptin (AP)-like prohormone in rat neonatal and adult cortical kidney cell cultures. However, these cultures contained proximal as well as distal tubular epithelial cells; thus characterization of the peptide synthetic cell was not possible. Also, by immunohistochemical techniques, we localized this AP-like prohormone to the distal cortical nephron in adult rat kidney. In this study, we examined further details of the kidney cortical cell type that expresses and secretes this AP-like peptide in adult renal cortical cell cultures, its regulation by adenylate cyclase via adenosine 3',5'-cyclic monophosphate (cAMP) generation, and its ability to stimulate guanylate cyclase. Tubular fragments were derived from cortical tissue of adult Sprague-Dawley rats and separated into four fractions on Percoll density gradient. Cell cultures generated from fraction 3 secreted 5- to 10-fold the amount of this renal peptide compared with fractions 2 and 4. Further cell culture characterization was performed by agonist-stimulated cAMP formation, kallikrein localization, and prostaglandin E2 formation. From these analyses, it was determined that tissue band 3 was enriched for distal cortical connecting tubules. To further evaluate whether mammalian distal nephron synthesizes an AP-like protein, we determined that two immortalized mouse cell lines, derived from either the distal convoluted tubule or cortical collecting tubule, synthesized a radiolabeled AP after being pulsed with [35S]-methionine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization, synthetic regulation, and biology of renal atriopeptin-like prohormone. 135 79

The effect of adenylate cyclase activators on C5a- and f-Met-Leu-Phe-induced human neutrophil aggregation, enzyme release and superoxide production was investigated. C5a-stimulated superoxide production was markedly inhibited by adenylate cyclase activators, and the order of potency was PGE1 greater than isoproterenol greater than epinephrine greater than PGF2 alpha, which correlated with intracellular cAMP levels. However, neutrophil aggregation was inhibited by PGE1, PGE2, isoproterenol and epinephrine only at concentrations greater than 10(-6) M. Lysozyme release was inhibited only via PGEs in the presence of the phosphodiesterase inhibitor, methylisobutylxanthine. These results suggest that in the human neutrophil: (1) C5a-induced superoxide production is more sensitive to regulation by cAMP than neutrophil aggregation or enzyme release, and (2) the type of receptor occupied as well as the threshold level of cAMP are important in the regulation of neutrophil aggregation and enzyme release stimulated by C5a.
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PMID:Effect of adenylate cyclase activators on C5a-induced human neutrophil aggregation, enzyme release and superoxide production. 137 1


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