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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)
The chemical carcinogen hydrazine is a potent stimulator of
guanylate cyclase
. In the present investigation we found that three chemical carcinogens structurally related to hydrazine, isonicotinic acid hydrazide, hydrazine
sulfate
, and dimethylhydrazine, decreased
guanylate cyclase
activity. It is of interest that hydrazine has been shown to increase DNA synthesis whereas isonicotinic acid hydrazide, hydrazine
sulfate
, and dimethylhydrazine decrease DNA synthesis. The relationship, if any, linking the
guanylate cyclase
-cyclic GMP system to DNA synthesis and carcinogenesis remains to be explored.
...
PMID:Effect of hydrazine, isonicotinic acid hydrazide, hydrazine sulfate, and dimethylhydrazine on guanylate cyclase activity. 3 Jun 19
The soluble form of
guanylate cyclase
from rat lung has been purified approximately 23,000-fold to homogeneity by isoelectric precipitation, GTP-Sepharose chromatography, and preparative gel electrophoresis. A single protein-staining band is observed after analytical gel electrophoresis on either 4 or 7.5% polyacrylamide gels. The final purified enzyme has a specific activity of about 700 nmol of cyclic GMP formed/min/mg of protein at 37 degrees C in the presence of 4.8 mM MnCl2 and 100 micrometer GTP. Bovine serum albumin appears to slightly increase
guanylate cyclase
activity, but mainly stabilizes the purified enzyme; in its presence, specific activities in excess of 1 mumol of cyclic GMP formed/min/mg of enzyme protein can be obtained. When Mg2+ or Ca2+ are substituted for Mn2+, specific activities decrease to approximately 21 and 40 nmol of cyclic GMP formed/min/mg of protein, respectively. The apparent Michaelis constant for MnGTP in the presence of 4.8 mM MnCl2 is 10.2 micrometer. Kinetic patterns on double reciprocal plots as a function of free Mn2+ are concave downward. The native enzyme has a molecular weight of approximately 151,000 as determined on Sephacryl S-200; sodium dodecyl
sulfate
-polyacrylamide gel electrophoresis results in two protein-staining bands with approximate molecular weights of 79,400 and 74,000. Thus, it appears that the soluble form of
guanylate cyclase
from rat lung exists as a dimer.
...
PMID:Purification of soluble guanylate cyclase from rat lung. 3 65
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.
...
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.
...
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.
...
PMID:[Guanylate cyclase in E. coli. III. Purification and possible physiological role of GTPase]. 4 Jun 73
One of the atrial natriuretic factor (ANF) receptors is a 180 kDa protein (180 kDa mGC) which possesses the extraordinary characteristic of being bifunctional: it is both a receptor and a
guanylate cyclase
. In addition to the 180 kDa mGC, there exists another 120-130 kDa protein which is also bifunctional and a 120 kDa disulfide-linked dimeric cell surface protein that is an ANF receptor, but is not a part of
guanylate cyclase
. A fundamental question that needs to be resolved is: Are these three apparently biochemically distinct ANF receptors structurally similar? With the aid of affinity crosslinking techniques, a highly specific antibody to the 180 kDa mGC, and GTP-affinity techniques, we now demonstrate the presence of three immunologically similar proteins in rat adrenal gland and testes. These proteins migrate as 180 kDa, 130 kDa and 65 kDa under denaturing sodium dodecyl
sulfate
polyacrylamide gel electrophoresis and specifically bind ANF, raising one or more of the following possibilities about their relationships: 1) Degradation of 180 kDa to 130 kDa and 65 kDa occurs during purification; 2) 180 kDa bears a precursor-product relationship with 130 kDa and 65 kDa, suggesting the role of a protease in the processing procedure; 3) these proteins are a result of gene splicing; or 4) they are the products of three separate, but very closely related genes.
...
PMID:Three immunologically similar atrial natriuretic factor receptors. 131 50
Atrial natriuretic peptide (ANP) binds to the
guanylyl cyclase
-A (GC-A) receptor found in tissues such as the kidney and adrenal gland, resulting in marked elevations of the intracellular signaling molecule, cGMP. Here, GC-A is shown to exist as a phosphoprotein when expressed in human embryonic 293 cells. The 32P is principally associated with phosphoserine, with only trace amounts of phosphothreonine. The addition of ANP causes a time-dependent dephosphorylation of the receptor, as well as desensitization, which is not due to an ANP-mediated decrease in the amount of receptor protein. The mobility of GC-A on sodium dodecyl
sulfate
-polyacrylamide gel electrophoresis increases after treatment of cells with ANP, and protein phosphatase 2A induces the same mobility shift. The protein phosphatase also catalyzes dephosphorylation of GC-A, and this is directly correlated with decreases in ANP-stimulatable
guanylyl cyclase
activity. Okadaic acid, an inhibitor of protein phosphatase 2A, blocks both the dephosphorylation and the desensitization. Therefore, in contrast to many other cell surface receptors, GC-A is desensitized by ligand-induced dephosphorylation.
...
PMID:Dephosphorylation of the guanylyl cyclase-A receptor causes desensitization. 135 76
Receptors for the Escherichia coli heat-stable enterotoxin (STa) were shown to be present throughout the digestive tract of the chicken, with binding activity present not only in the intestinal epithelium but also in the intestinal smooth muscle. Brush border membrane vesicles (BBMV) purified from chicken enterocyte homogenates and plasma membranes (SMPM) purified from intestinal smooth muscle homogenates were compared with pig enterocyte BBMV. All had similar 125I-STa binding affinities, but the 50% effective concentration for STa activation of
guanylate cyclase
was higher in SMPM than in BBMV. Maximal STa-stimulated
guanylate cyclase
activities were similar in chicken and pig BBMV and were seven- to eightfold higher than in SMPM, and the STa receptor density was five- to sixfold higher. Patterns unique to each membrane were demonstrated after affinity labelling of STa receptors with 125I-STa, sodium dodecyl
sulfate
-polyacrylamide gel electrophoresis, and autoradiography. The results demonstrated STa-stimulated
guanylate cyclase
activity in birds as well as mammals and suggested that there are different functional STa receptors in chicken BBMV and SMPM.
...
PMID:Presence of functional receptors for the Escherichia coli heat-stable enterotoxin in the gastrointestinal tract of the chicken. 135 99
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.
...
PMID:Cloning, expression, and crystallization of recoverin, a calcium sensor in vision. 138 64
Intestinal brush border membranes from 1-day-old and 4-week-old (day of weaning) pigs were affinity labeled with an Escherichia coli heat-stable enterotoxin (STa) by cross-linking 125I-STa to receptor proteins with disuccinimidyl suberate. Analysis by sodium dodecyl
sulfate
-polyacrylamide gel electrophoresis and autoradiography revealed that a radioactive protein with a relative molecular weight of 137,000 to 145,000 was present in both age groups. A strongly radioactive protein with an apparent Mr of 90,000 was present in the 1-day-old animals but not in those that were 4 weeks old. The major radioactive protein present in the older pigs had an Mr of 64,000 to 67,000, but this protein was missing or very weakly radioactive in the younger pigs. There was no significant difference between the groups in receptor affinity for STa, although the receptor density in the older animals was marginally significantly greater. STa-stimulated
guanylate cyclase
activity in membranes from 1-day-old pigs was only one-sixth that in 4-week-old pigs, although the basal and Lubrol PX-stimulated activities were similar.
...
PMID:Age-dependent changes in affinity-labeled receptors for Escherichia coli heat-stable enterotoxin in the swine intestine. 168 59
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