Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Guanylate cyclase activity is present in crude E. coli extract. Guanylate cyclase has been purified 3500 fold from this extract, through ammonium sulfate fractionation, DEAE-cellulose chromatography. Sephadex G-75 gel-filtration and polyacrylamide gel preparative microelectrophoresis. During the purification a guanylate cyclase inhibitor has been separated.
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PMID:[Guanylate cyclase in Escherichia coli. I. Purification of the enzyme and evidence for an inhibitor]. 3 97

Enterotoxin derived from three clinical isolates of Yersinia enterocolitica was compared with the heat-stable enterotoxin of Escherichia coli. Both toxins were biologically active in infant mice examined at 2 h and in ligated rabbit ileal loops at 6 h. Neither substance, however, produced changes in ligated ileal loops at 18 h or in Chinese hamster ovary or Y1 adrenal tissue cultures. In addition, both Y. enterocolitica enterotoxin concentrated approximately 20 times by ammonium sulfate precipitation and ultrafiltration and a similarly prepared sample of E. coli heat-stable enterotoxin stimulated the activity of guanylate cyclase but not that of adenylate cyclase in infant mouse intestine. These findings suggest that the role of enterotoxin in the pathogenesis of intestinal Y.enterocolitica infection may be similar to that of heat-stable enterotoxin in E. coli diarrhea.
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PMID:Mechanism of action of Yersinia enterocolitica enterotoxin. 3 94

A phosphohydrolase with a preferential activity for GTP has been isolated and partially purified from E. coli extracts. The enzyme purification has been achieved through precipitation by ammonium sulfate and chromatography on DEAE-cellulose, DEAE-Sephadex, Ultragel and a second DEAE-cellulose column. The phosphohydrolase activity is poly (C) dependent. The chromatographic analysis on PEI-cellulose has shown that the main product of GTP hydrolysis is GDP. The possibility that the enzyme partially purified in this work has an important role in the control of GTP availability as substrate for guanylate cyclase into the cells has been discussed.
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PMID:[Guanylate cyclase in E. coli. III. Purification and possible physiological role of GTPase]. 4 Jun 73

Recoverin, a recently discovered 23-kDa calcium-binding protein, activates retinal rod guanylate cyclase when the calcium level is lowered in the submicromolar range. We report here the cloning and sequencing of a cDNA for recoverin from a bovine retinal expression library. The recoverin coding sequence was inserted into a pET-11a expression vector under control of the T7 phage promoter. A second expression system, in which the coding sequence was placed under control of the lambda phage PR promoter, gave 10-fold higher yields (10 mg of purified recoverin per liter of Escherichia coli culture). The finding that retinal recoverin is myristoylated at its amino terminus led us to coexpress the recombinant protein and N-myristoyltransferase (EC 2.3.1.97). Myristoylated recombinant recoverin formed in this way in E. coli is like retinal recoverin in exhibiting a large calcium-induced shift in its tryptophan fluorescence emission spectrum. The availability of abundant protein enabled us to crystallize unmyristoylated recombinant recoverin and initiate x-ray studies. The space group of tetragonal crystals obtained from 75% saturation ammonium sulfate is I4 with unit cell dimensions a = 85.1 A and c = 59.8 A. These crystals of the calcium-bound form of the protein diffracted to a resolution of 2.2 A. The expression systems described here open the door to high-resolution x-ray crystallographic and nuclear magnetic resonance studies of this new member of the EF-hand superfamily and to the elucidation of its precise mode of action as a calcium switch.
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PMID:Cloning, expression, and crystallization of recoverin, a calcium sensor in vision. 138 64

L-Arginine-derived nitric oxide acts as an inter- and intracellular signal molecule with cytosolic guanylyl cyclase as the effector system. Two NO synthase isoenzymes are postulated: a cytokine-inducible enzyme in macrophages and a constitutive, Ca2(+)-regulated enzyme in various other cells. An NO synthase was isolated from porcine cerebellum by ammonium sulfate precipitation and affinity chromatography on 2',5'-ADP-Sepharose. The enzyme was identified as an NO synthase with a specific NO-chemiluminescence method and with purified cytosolic guanylyl cyclase as an NO-sensitive detection system. The purified NO synthase was, besides Ca2+/calmodulin and NADPH, largely dependent on tetrahydrobiopterin as a cofactor.
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PMID:Purification of a Ca2+/calmodulin-dependent nitric oxide synthase from porcine cerebellum. Cofactor-role of tetrahydrobiopterin. 170 32

Experiments were designed to determine the mechanism of action underlying relaxation of vascular smooth muscle induced by ammonium ions. In particular, the possibility that these ions might be an endothelium-derived relaxing factor was examined. Rings of large canine femoral, mesenteric and coronary arteries and of small arteries from the gracilis muscle were suspended in organ chambers for the recording of isometric force. Membrane potential was recorded with intracellular microelectrodes in smooth muscle cells from the mesenteric artery. Ammonium ions induced relaxation which were independent of the presence of the endothelium. The relaxations were not prevented by adrenergic, serotonergic, muscarinic and histaminic blockers, by scavengers of oxygen-derived radicals or by inhibitors of soluble guanylate cyclase. The relaxations were prevented by a decrease in extracellular calcium concentration and by inhibition of the Na+/K+ pump. The results are compatible with the hypothesis that the relaxation induced by ammonium ions is related to changes in intracellular pH and, at high concentration of these ions, possibly to activation of the Na+/K+ pump. Ammonium ions are neither the endothelium-derived relaxing factor which activates guanylate cyclase nor the factor that induces endothelium-derived hyperpolarization. Inasmuch as relatively low concentrations of the ion induce relaxation of small arteries of skeletal muscle, they could contribute to exercise hyperemia.
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PMID:Ammonium ions cause relaxation of isolated canine arteries. 257 25

When Arbacia punctulata spermatozoa are incubated in seawater containing ammonium hydroxide (pH 8.8), the sperm plasma membrane-bound guanylate cyclase is dephosphorylated, its electrophoretic mobility increases (from an apparent molecular mass of 160 to 150 kD), and its enzymatic activity decreases 3.5-fold. Transfer of these cells into ammonium-free seawater (pH 7.4) results in the rephosphorylation of the cyclase, its reconversion to 160 kD, and recovery of the enzymatic activity lost upon dephosphorylation. This is the first direct demonstration that the activity of membrane-bound guanylate cyclase can be regulated by phosphorylation. A plasma membrane preparation is described that specifically supports the in vitro phosphorylation of the guanylate cyclase. This preparation will be useful in more detailed studies on the relationship between phosphorylation state and enzymatic activity of membrane-bound guanylate cyclase.
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PMID:Phosphorylation of membrane-bound guanylate cyclase of sea urchin spermatozoa. 287 44

Murine neuroblastoma cells (clone N1E-115) possess both high- and low-affinity muscarinic receptors. The low-affinity muscarinic receptor, when stimulated, initiates the formation of cyclic GMP by activating the enzyme guanylate cyclase; whereas stimulation of the high-affinity receptor inhibits prostaglanding E1-mediated cyclic AMP formation by inhibiting the enzyme adenylate cyclase. We have reported that lithium ion (Li+) inhibits cyclic GMP formation mediated by the muscarinic receptor agonist, carbachol, in a concentration-dependent manner and that neither ammonium nor sodium ions have such an effect. We extended this study to show that Li+ was an apparently noncompetitive inhibitor of the low-affinity muscarinic receptor with an IC50(+/- SEM) = 13.6 +/- 0.8 mM. In addition, Li+ with a similar IC50 inhibited the cyclic GMP response in intact cells to sodium azide, which is thought to stimulate guanylate cyclase directly. Moreover, though Li+ was found to have a slight inhibitory effect on prostaglandin E1-stimulated cyclic AMP formation (15% inhibition at 10 mM), it had no effect on the function of the high-affinity muscarinic receptor in intact murine neuroblastoma cells.
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PMID:Lithium ions inhibit function of low- but not high-affinity muscarinic receptors of murine neuroblastoma cells (clone N1E-115). 299 50

Soluble guanylate cyclase (GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2) has been purified to apparent homogeneity from rat brain by chromatography on Blue-Sepharose CL-6B, precipitation with (NH4)2SO4, preparative isoelectric focusing and gel-filtration on Ultrogel AcA-34. On sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis the purified enzyme showed a single band with an apparent molecular weight 59 000, when stored in buffer without glycerol and 2-mercaptoethanol. Purified enzyme has been found to be very unstable; inactivation can however be partially reversed by an endogenous heat-stable activator fraction. A monospecific antiserum obtained by immunization of rabbits was found to precipitate guanylate cyclase. This antibody also reacted with membrane-bound enzyme, indicating a close similarity to the soluble enzyme. Metal divalent cations were in general found to be strong inhibitors of the enzyme activity, though Ca2+ had no effect. ATP, CTP or UTP were shown to be competitive inhibitors of purified guanylate cyclase. Sodium nitroprusside increased cyclic GMP formation by the purified enzyme. Lysophosphatidylcholine and oleic acid, at low concentration, activated guanylate cyclase. Other unsaturated fatty acids, particularly arachidonic acid, dramatically inhibited the enzyme activity. Lipids may regulate the enzyme activity by binding to an apolar domain, as suggested by charge-shift electrophoresis. The mechanism by which guanylate cyclase is regulated in the cell appears to be a complex phenomenon. It may occur through oxidative reductive processes, and/or depend on other effectors, such as triphospho-nucleotides, divalent cations and lipid microenvironment.
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PMID:Rat brain guanylate cyclase. Purification, amphiphilic properties and immunological characterization. 611 51

A soluble, sodium-nitroprusside-stimulated guanylate cyclase as been purified from bovine lung by DEAE-cellulose chromatography, ammonium sulfate precipitation, chromatography on Blue Sepharose CL-6B and preparative gel electrophoresis. Apparent homogeneity was obtained after at least 7000-fold purification with a yield of 3%. A single stained band (Mr 72000) was observed after gel electrophoresis in the presence of sodium dodecyl sulfate. The purified enzyme migrated as one band also under non-denaturing conditions in acrylamide gels (5-12%). The mobility of this band corresponded to an Mr of 145000. The enzyme sedimented on sucrose gradients with an S20, w of 7.0 S. Gel filtration yielded a Stokes' radius of 4.6 nm. These data suggest that the enzyme has an Mr of approximately 150000 and consists of two, presumably identical, subunits of Mr 72000. Sodium nitroprusside stimulated the purified enzyme 15-fold and 140-fold to specific activities of 8.5 and 15.7 mumol of cGMP formed min-1 mg-1 in the presence of Mn2+ and Mg2+, respectively. Formation of cGMP was proportional to the incubation time and to the amount of enzyme added. The stimulatory effect of sodium nitroprusside was half-maximal at about 2 microM, was observed immediately after addition and could be reversed either by dilution or by removal of sodium nitroprusside on a Sephadex G-25 column. The purified enzyme in the absence of catalase was stimulated by sodium nitroprusside, N-methyl-N'-nitro-N-nitrosoguanidine and 3-morpholino-sydnonimine and in the presence of catalase by sodium nitrite and sodium azide. In the presence of Mn2+ and sodium nitroprusside, the purified enzyme catalyzed the formation of cAMP from ATP at a rate of 0.6 mumol min-1 mg-1.
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PMID:Purification of a soluble, sodium-nitroprusside-stimulated guanylate cyclase from bovine lung. 611 59


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