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 mechanism of cholinergic stimulation of alanine and glutamine formation and release from skeletal muscle was studied using rat epitrochlaris preparations. The increased alanine and glutamine release produced by carbamylcholine (10(-6) M) was reproduced by tetramethylammonium (10(-6) M) but not by pilocarpine (10(-6) M) and was blocked by hexamethonium (10(-4) M) but not by atropine (10(-7) M). This increased alanine and glutamine release was not associated with altered muscle cAMP levels. However, carbamylcholine (10(-6) M) and tetramethylammonium (10(-6) M) did not increase levels of cGMP, 134% and 101%, respectively, and these increments in cGMP were blocked by hexamethonium but not by atropine. Carbamylcholine produced a concentration-dependent increase in cGMP levels. Methylisobutylxanthine and theophylline augmented the increased amino acid release and increased cGMP levels produced by carbamylcholine. Neither xanthine derivative alone altered alanine and glutamine release or cyclic nucleotide levels. Added cGMP increased amino acid release and the uptake of [U-14C]alanine and alpha-amino[14C]isobutyric acid. Carbamylcholine did not alter muscle phosphorylase a activity, glycogen levels, or basal adenylate cyclase activity. These data indicate that cholinergic stimulation of muscle alanine and glutamine formation and release involves a nicotinic cholinergic receptor and may be mediated by increased levels of cGMP, which in turn may result from a cholinergic stimulation of muscle guanylyl cyclase.
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PMID:Cholinergic stimulation of skeletal muscle alanine and glutamine formation and release. Evidence for mediation by a nicotinic cholinergic receptor and guanosine 3':5'-monophosphate. 8 Dec 8

Adenylate cyclase of Brevibacterium liquefaciens depends on pyruvate for activity. Growing in a simple medium containing glucose and DL-alanine, the microorganism excreted pyruvate, which reached 20 mM in the medium at stationary phase. Using [3H]adenosine to label the adenosine 5'-triphosphate pool, we showed that pyruvate in the medium stimulated adenylate cyclase of B. liquefaciens in vivo, in a manner similar to the stimulation observed in vitro. Adenylate cyclase in cells harvested at different phases of growth was equally responsive to exogenous pyruvate, indicating that the allosteric site for pyruvate was present in the enzyme throughout the various phases of cell growth. The specific activity of adenylate cyclase was highest in cells harvested at early log phase; thereafter it declined and was substantially lower at stationary phase. Although adenylate cyclase appears to be activated by pyruvate throughout the life span of the cell, the activity appears not to be critical to cell growth, which was comparable whether the medium contained high or low pyruvate.
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PMID:Brevibacterium liquefaciens adenylate cyclase and its in vivo stimulation by pyruvate. 17 86

Alanine and glutamine formation and release were studied using the intact epitrochlaris preparation of rat skeletal muscle. Epinephrine reduced the release of alanine and glutamine in a concentration-dependent manner. Measurable inhibition was observed at 10(-9) M epinephrine, and maximal inhibition was obtained at 10(-5) M. Norepinephrine also reduced alanine and glutamine formation and release but the concentration required for maximal inhibition was approximately 100-fold greater than for epinephrine. Isoproterenol (beta agonist), but not phenylephrine (alpha agonist), reproduced the effects of epinephrine, and propranolol (beta antagonist), but not phentolamine (alpha antagonist), blocked the effect of the catecholamine. N6,O2'-Dibutyryl adenosine 3':5'-monophosphate reproduced the effects of epinephrine and theophylline potentiated the effect of submaximal concentrations of the hormone. Glucagon and prostaglandin E2 had no observable effect on amino acid release. Insulin did not modify the inhibition of alanine and glutamine release produced by epinephrine. Alanine and glutamine formation from added precursor amino acids was unaffected by epinephrine or cyclic adenosine 3':5'-monophosphate. Epinephrine reduced alanine formation in muscles obtained from diabetic rats or animals treated with thyroxine or cortisone. These findings indicate that physiological levels of catecholamines reduce alanine and glutamine formation and release from skeletal muscle. This effect is mediated by a beta-adrenergic receptor and the adenylate cyclase system and can be accounted for by an inhibition of muscle protein degradation.
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PMID:Alanine and glutamine synthesis and release from skeletal muscle. IV. beta-Adrenergic inhibition of amino acid release. 17 62

The ability of three analogs of ACTH1-24 ([Gln5, Phe9] ACTH1-24, [Gln5, Ala9[Acth1-24, and [Gln5, Lys8, Phe9[ ACTH1-24) embodying tryptophan substitutions to activate the adenylate cyclase system of a bovine adrenal plasma membrane preparation was compared to the effect of the analogs on adenosine 3':5'-monophosphate (cyclic AMP) accumulation and steroidogenesis in viable bovine adrenocortical cells. The results were not comparable. Whereas the analogs antagonized the ACTH1-24-activated membrane cyclase they stimulated cyclic AMP accumulation as well as steroid production of the cells. None of the analogs inhibited steroidogenesis of ACTH1-24-stimulated cells, but two of them, at very high dose levels, inhibited cyclic AMP production. The ability of the analogs to stimulate steroidogenesis of the adrenal cells half-maximally decreased in the order tryptophan greater than phenylalanine greater than alanine, indicating that the aromaticity of the indole ring of tryptophan is necessary for maximal interaction between hormone and receptor. Both the absolute and relative steroidogenic potencies were the same for several analogs when assayed with rat adrenal cells. Although only a small fraction of the cell's potential to produce cyclic AMP was necessary to induce maximum steroid production, the relative activities of a series of analogs were the same for steroidogenesis as for cyclic AMP accumulation. Furthermore, the concentration of cyclic AMP necessary for full steroidogenesis was practically identical for a series of peptides that differed widely in potency. These findings support the postulate that cyclic AMP accumulation and steroidogenesis in adrenocortical cells are coupled processes. The differential behavior of bovine adrenal plasma membranes and bovine adrenocortical cells toward ACTH analogs indicates that structure-function studies using cyclase assays may not reflect events that take place in the intact adrenal or in cell preparations derived therefrom.
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PMID:Differential response to adrenocorticotropic hormone analogs of bovine adrenal plasma membranes and cells. 18

It had been reported by authors that salivary gland hormone, parotin, was composed with subunit (parotin-subunit) which showed molecular weight of 45,000, and that parotin-subunit had rabbit serum calcium decreasing activity and the cross reactivity with rabbit anti parotin serum. In the present report, in order to study physiological chemistry of parotin-subunit, the influence of parotin-subunit on serum Ca and 45Ca levels relating to calcium metabolism, the distribution of 131I-parotin-subunit, the effect of parotin-subunit, on adenyl cyclase-cyclicAMP system, the anabolic action, C-terminal amino acid sequence and sugar component of parotin-subunit were investigated. The results are summarized as follows: 1) The decrease of rabbit serum Ca after injection of parotin-subunit was related to change of Ca in stable bone, but not to inhibition of bone resorption. 2) A high concentrated localization of radioactivity of 131I-parotin-subunit was found in liver, kidney and spleen, and as much as 60% of administrated radioactivity was localized in liver at 5 min after the injection. The retention of radioactivity was found in testis, seminal vesicle, prostate, parotid gland and submaxillary gland. 3) Cyclic AMP level increased significantly in metaphysial bone, submaxillary gland and plasma after administration of parotin-subunit but in other organs with localized much radioactivities, the level did not changed. Parotin-subunit activated adenyl cyclase of particular fraction of metaphysial bone. 4) The C-terminal amino acid of parotin-subunit was Leu, and its C-terminal amino acid sequence was -Val-Ser-Ala-Thr- Leu-OH by digestion of carboxypeptidase A. 5) Parotin-subunit included 3.3% of sugar which consisted of amino sugar and uronic acid.
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PMID:[The study of physiological chemistry on a subunit of salivary gland hormone (2) (author's transl)]. 18 2

The mechanism of the increased alanine and glutamine formation and release from skeletal muscle in experimental uremia was investigated using epitrochlearis preparations from control and chronically uremic rats. In uremic muscle, insensitivity to epinephrine or serotonin suppression of alanine and glutamine release was observed. With control muscles, 1 nm or greater, epinephrine inhibited alanine and glutamine release, whereas with uremic muscles, epinephrine concentrations <1 muM did not alter amino acid release. Decreased alanine and glutamine release with 1 nM serotonin was observed in control muscles, but no inhibition was observed with concentrations <1 muM in uremic muscle. Muscle amino acid levels were the same in control and uremic muscles in the presence or absence of epinephrine or serotonin. The reutilization of released alanine by protein synthesis or oxidation to CO(2) was not differentially affected by epinephrine in uremic muscles as compared with control muscle. Dibutyryl-cAMP inhibited amino acid release equally in uremic and control muscles. Epinephrine or serotonin increased cAMP levels two- to four-fold or more in control than in uremic muscle. Basal- and fluoride-stimulated adenylate cyclase activities were equal in uremic and control muscle homogenates and in membrane fractions, but 10 muM epinephrine-stimulated adenylate cyclase was reduced 30-60% with uremia. At any concentration of epinephrine (0.001-100 muM), the stimulation of membrane adenylate cyclase activity was one- to twofold greater with control membranes than with uremic muscle membranes. With either control or uremic muscle, peak adenylate cyclase activity was observed at 1 muM epinephrine. These data indicate that skeletal muscle in chronic uremia acquires an insensitivity to the metabolic action of epinephrine or serotonin. This insensitivity may be attributable in part to the diminished increments in muscle cAMP levels produced by adrenergic and serotonergic agonists. The decreased cAMP levels may derive in turn from a decreased activity or subsensitization of the agonist-stimulated adenylate cyclase in uremic muscle.
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PMID:The regulation of skeletal muscle alanine and glutamine formation and release in experimental chronic uremia in the rat: subsensitivity of adenylate cyclase and amino acid release to epinephrine and serotonin. 21 Nov 45

Angiotensin II effects on cyclic AMP production and steroid output were studied in a sensitive preparation of isolated rat adrenal glomerulosa cells. With increasing concentrations of angiotensin II logarithmic dose-response curves for aldosterone and cyclic AMP production were similar. The minimum effective dose (0.2nm) for stimulation of aldosterone production also significantly (P<0.001) increased cyclic AMP output. For both aldosterone and cyclic AMP production, the peptide hormone concentration eliciting maximal response (0.2mum) and the ED(50) (median effective dose) values (1nm) were the same; this is consistent with cyclic AMP acting as an intracellular mediator for angiotensin II-stimulated aldosterone production by glomerulosa cells. The angiotensin II antagonist [Sar(1),Ala(8)]angiotensin II inhibited angiotensin II-stimulated corticosterone and aldosterone production in these cells. An equimolar concentration of antagonist halved the response to 20nm-angiotensin II, and complete inhibition was observed with 0.2mum-antagonist. In contrast, [Sar(1),Ala(8)]angiotensin II had no effect on maximally stimulated steroidogenesis induced by serotonin and a raised extracellular K(+) concentration. Increasing concentrations of [Sar(1),Ala(8)]angiotensin II alone decreased corticosterone and aldosterone outputs significantly (P<0.05) at concentrations of 20nm and 2nm of antagonist respectively. A significant (P<0.001) decrease in cyclic AMP production occurred with 2mum antagonist and this was comparable with the decrease in aldosterone production. It is concluded that [Sar(1),Ala(8)]angiotensin II can independently affect glomerulosa-cell steroidogenesis, possibly by modulating adenylate cyclase activity.
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PMID:Adenosine 3':5'-cyclic monophosphate production and steroidogenesis by isolated rat adrenal glomerulosa cells. Effects of angiotensin II and [Sar 1,Ala 8]angiotensin II. 21 34

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

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
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PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

The methods utilized in our laboratory for a biochemical approach of obesity include dietary manipulations, fatty acid analysis of tissue lipids, in vivo lipogenesis from [3H H2O and [1-14C] acetate, in vitro utilization of [3H] H2O, [U-14C] glucose, [U-14C] fructose, [U-14C] alanine and [1-14C] acetate by adipose tissue fragments, hormone sensitivity (to insulin and catecholamines), and the activity of enzymes such as fatty acid synthetase and adenylate cyclase in adipose tissue extracts. With these methods at hand, it is possible to estimate the major biochemical factors responsible for fat accumulation in adipose tissue. As an example, the case of obese (ob/ob) homozygotic animals of the C57BL/6J strain of Bar Harbor, which suffer from an autosomal recessive obese-hyperglycemic (O-H) syndrome, is compared to that of control nonobese (ob+/ob+) mice from the same strain. The hereditary O-H syndrome in ob/ob mice is characterized by obesity, resistance to the action of insulin, and hyperinsulinism. The development of obesity depends on high lipogenesis in fat depots. Contribute also to obesity a large influx of fatty acids of hepatic and dietary origin, and reduced lipolysis. In these mice, a high fat diet is more propitious to fat accretion than a high-carbohydrate diet.
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PMID:Experimental basis of obesity. 62 36


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