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

Guanylate cyclase from rod photoreceptors of amphibian (toad, Bufo marinus, and frog, Rana catesbeiana) and bovine retinas was solubilized and purified by a single chromatography step on a GTP-agarose column. Silver staining of purified amphibian enzymes in SDS/polyacrylamide gels disclosed a doublet band (110 and 115 kDa), while the bovine enzyme appeared as a singlet band (110 kDa). The identification of these guanylate cyclases was confirmed using three chromatography systems with the purified enzymes. Specific binding to Con A-Sepharose suggested that rod guanylate cyclase is a glycoprotein. Two-dimensional gel electrophoresis of purified toad, frog, and bovine enzymes resolved two, three, and five variants, respectively, that differed in isoelectric point. Two variants of toad guanylate cyclase showed differences in various characterizations. These data suggest multiple mechanisms for regulation of guanylate cyclase activity in vertebrate rod photoreceptors.
 ...
PMID:Polymorphism in purified guanylate cyclase from vertebrate rod photoreceptors. 167 87

In vitro autoradiographic studies showed that high-affinity atrial natriuretic factor (ANF) binding sites are present on rat choroid plexus (Kd = 83.8 pM, Bmax = 22.9 fmol/mg protein). Guanylate cyclase-coupled receptors (ANF-R1) represent 30% and non-guanylate cyclase-coupled ANF receptors (ANF-R2) represent 70% of the total ANF receptors present in this tissue. To provide detailed cellular localization of the binding sites, the technique of electron-microscopic autoradiography was applied using 125I-ANF (Ser 99-Tyr 126) as an in vivo ligand. In order to identify possible binding sites at the basolateral and the apical aspects of the choroid plexus, the ligand was injected into the carotid artery or into the lateral cerebral ventricles, respectively. Light-microscopic autoradiography demonstrated that ANF binds specifically to choroid plexus regardless of its route of administration. Electron-microscopic autoradiography showed that silver grains were localized primarily on epithelial cells of the choroid plexus (96-99%) and marginally on endothelial and pial cells. In choroidal epithelial cells, ultrastructural analysis of silver grain distribution revealed that, at 2 min after intracarotid or intracerebroventricular 125I-ANF injection, lysosomes were the most distinctly labeled organelle (highest relative specific radioactivity). HPLC Chromatographic analysis disclosed that 96-99% of choroid plexus-bound ANF was already degraded 2 min after injection and that at least 63-66% of the degradation took place at the plasma membrane. These results indicate that ANF binding sites are present on both aspects of choroidal epithelium, and suggest that ANF is very quickly degraded in choroid plexus by membrane-associated as well as lysosome-associated processes.
 ...
PMID:Localization and characterization of binding sites for circulating and cerebroventricular atrial natriuretic factor in rat choroid plexus. 215 94

The atrial natriuretic factor (ANF) R1 receptor from bovine adrenal zona glomerulosa was solubilized with Triton X-100 and purified 13,000-fold, to apparent homogeneity, by sequential affinity chromatography on ANF-agarose and steric exclusion high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining of the purified receptor preparation in the absence or presence of dithiothreitol revealed a single protein band of Mr 130,000. Affinity cross-linking of 125I-ANF to the purified receptor resulted in the labeling of the Mr 130,000 band. The purified receptor bound ANF with a specific activity of 6.8 nmol/mg of protein, corresponding to a stoichiometry of 0.9 mol of ANF bound/mol of Mr 130,000 polypeptide. Starting with 500 g of adrenal zona glomerulosa tissue, we obtained more than 500 pmol of purified receptor with an overall yield of 9%. The purified receptor showed a typical ANF-R1 pharmacological specificity similar to that of the membrane-bound receptor. The homogeneous Mr 130,000 receptor protein displayed high guanylate cyclase activity [1.4 mumol of cyclic GMP formed min-1 (mg of protein)-1] which was not stimulated by ANF. This finding supports the notion that the ANF binding and the guanylate cyclase activities are intrinsic components of the same polypeptide. Finally, the purified ANF-R1 receptor retained its sensitivity to modulation by amiloride, suggesting the presence of an allosteric binding site for amiloride on the receptor protein.
 ...
PMID:Atrial natriuretic factor R1 receptor from bovine adrenal zona glomerulosa: purification, characterization, and modulation by amiloride. 285 53

The receptor for the Escherichia coli heat-stable enterotoxin has been characterized and partially purified from the T84 human colonic cell line. Using a novel mutant heat-stable enterotoxin peptide as a radioligand (the C-terminal tyrosine residue is replaced by phenylalanine in the mutant), a single class of high-affinity receptor sites was detected in T84 cells, with a Kd of 0.1 nM, similar in affinity to the receptor described in human intestinal tissue. The receptor was solubilised from T84 cell membranes and affinity cross-linking of the solubilised preparation indicated that a single species of M(r) 160,000 served as the receptor. Freshly solubilised preparations of the receptor retained heat-stable enterotoxin-activable guanylyl cyclase activity. Purification of the receptor was achieved through sequential affinity chromatography on GTP--epoxy-Sepharose and wheat-germ-agglutinin columns resulting in purification of the receptor by 3000 fold. The heat-stable enterotoxin-binding characteristics of the receptor were unchanged during the purification and silver staining of the purified receptor preparation indicated a band of M(r) 160,000, which was specifically cross-linked to the 125I-labeled mutant peptide. The purified receptor retained guanylyl cyclase activity, but the activity was not stimulated on addition of human heat-stable enterotoxin, suggesting that accessory structural factors may be involved in the activation of the guanylyl cyclase/receptor.
 ...
PMID:Characterization and partial purification of the human receptor for the heat-stable enterotoxin. 790 48

By use of the polymerase chain reaction (PCR), uniform amplification products of 225 to 240 bp length were obtained from five cDNA clones representing different types of guanylyl cyclases. These short DNA double strands were differentiated by single-strand conformation polymorphism (SSCP), using polyacrylamide gel electrophoresis with the Pharmacia Phast-System. Following heat denaturation, the samples were separated on native polyacrylamide gels at different running temperatures. Nucleic acids on the gel were detected by an automated silver stain procedure. Using 7.5% homogeneous or 4-15% gradient polyacrylamide gels at a temperature of 12 degrees C, single-strand conformations of amplificates, representing three different particulate guanylyl cyclases and the two subunits of soluble guanylyl cyclase, were differentiated. The characteristic banding patterns resulting from dissimilar migration of the single-strand conformations were assigned to different guanylyl cyclase types. For the enzyme family of guanylyl cyclases, the feasibility of a combined PCR and electrophoresis approach for analyzing the expression of related genes was demonstrated. This application of the PCR-SSCP technique provided a rapid and sensitive tool for the characterization of PCR products obtained with a common primer pair and suggested its use for investigating the tissue distribution of gene expression within a class of homologous proteins.
 ...
PMID:Distinction of weakly homologous cDNA amplificates by single-strand conformation polymorphism analysis: application to guanylyl cyclase isozymes. 792 29

The activation of nitric oxide synthase (NOS) has been linked to excitatory input via NMDA receptors. We hypothesized that NOS-positive neurons that have NMDA receptors on their surface would have high levels of cytochrome oxidase (C.O.) as energy generator for membrane repolarization. In order to compare the distribution of these markers on the same section, we reacted rat brain sections for C.O. histochemistry followed by NOS immunogold silver staining (IGSS). Adjacent sections were reacted for NOS IGSS followed by indirect immunoperoxidase for NMDA receptor subunit R1 (NMDAR1). We found that the staining pattern varied among regions but were consistent within each region examined. There are three types of NOS immunoreactive (NOS-ir) cells: (1) NOS-ir neurons that had moderate to high levels of both NMDAR1 and C.O. staining, such as the pontine reticular nuclei, motor and mesencephalic nuclei of the trigeminal nerve, and some motor neurons in the spinal cord. (2) NOS-ir neurons that were immunoreactive for NMDAR1 (NMDAR1-ir) but had low levels of C.O. activity in thei- somata. Their dendrites, however, were both NMDAR1-ir and rich in C.O. Examples of this type include neurons in the caudate and putamen, and periglomerular cells in the olfactory bulb. (3) We also found that some NOS-ir neurons were not NMDAR1-ir and had low C.O. activity. In addition to postsynaptic neurons, C.O. and NOS levels were both high in the inner segments of retinal photoreceptor cells where energy-demanding active ion transport maintains the dark current and where NO presumably activates guanylate cyclase for the production of cGMP, which keeps the Na+ channels open in the dark. Our findings suggest that NMDA receptors are available for the majority of NOS-ir neurons, which comprise a heterogenous population with varying energy demands.
 ...
PMID:Do nitric oxide synthase, NMDA receptor subunit R1 and cytochrome oxidase co-localize in the rat central nervous system? 887 89

Conserved sequences within gene families permit the design of consensus primers that match several members of a given class of homologous genes. Polymerase chain reaction (PCR) products obtained with such consensus primers were characterized by restriction mapping or single-strand conformation polymorphism (SSCP) analysis, using precast polyacrylamide minigels and automated silver staining. Examples for the electrophoretic distinction of consensus amplificates are presented in the fields of guanylyl cyclase expression studies and in the determination of B-cell clonality in human blood samples. Guanylyl cyclase expression in inner ear tissues of guinea pigs was investigated by reverse transcription PCR using consensus primers with specificity for the subclass of particulate guanylyl cyclases. The resulting PCR products were assigned to three representatives of this group by restriction mapping. The consensus PCR approach enabled the detection of an unexpected receptor type, namely guanylyl cyclase C, in the inner ear. The distinction by SSCP analysis of denatured consensus amplificates was appropriate for the identification of clone-specifically rearranged immunoglobulin heavy chain genes of B-lymphocytes. Genomic DNA isolated from blood samples of leukemia patients served as the template for the consensus amplification of clone-specific VDJ rearrangements. Rapid distinction and re-identification of consensus PCR products was achieved by SSCP analysis for regular antigen receptor rearrangements and for t(14; 18) translocations. The potential of these procedures for detecting leukemia or lymphoma clones when monitoring minimal residual disease was assessed.
 ...
PMID:Applications of consensus polymerase chain reaction with subsequent electrophoretic distinction of amplificates. 923 62

Complementary DNA fragments for two isoforms of particulate guanylate cyclase C (GC-C) were cloned from the intestine of the European eel (Anguilla anguilla). Both isoforms exhibited higher nucleotide and amino acid sequence homologies to members of the GC-C family from other species than the related guanylate cyclase A or B (GC-A or GC-B) isoforms from the eel. Northern blots indicated that probes for both isoforms, termed GC-C1 and GC-C2, selectively hybridised to 4.8-kb transcripts in the intestine and the kidney. Expression of the GC-C2 transcript in the intestine was increased by 100% following the transfer of yellow FW-acclimated eels to SW. Likewise developmental maturation of yellow eels into pre-migratory silver eels resulted in a significant increase (60%) in the intestinal expression of GC-C2. No changes in expression of GC-C2 were seen in the kidney under any condition. RT-PCR indicated that the GC-C2 isoform is only expressed in anterior and mid-gut segments in FW-acclimated yellow eels. However, expression is also extended to the posterior gut segment when yellow eels are acclimated to SW or following developmental transformation into silver eels.
 ...
PMID:Cloning and expression of two isoforms of guanylate cyclase C (GC-C) from the European eel (Anguilla anguilla). 1139 93

Three guanylin-like peptides, guanylin, uroguanylin and renoguanylin and two guanylate cyclase type C (GC-C) receptor isoforms were cloned and sequenced from the European eel (Anguilla anguilla). All peptides and both receptors (GC-C1 and GC-C2) were predominantly expressed within the intestine and kidney of both sexually immature yellow, and sexually maturing, migratory silver eels. The derived amino acid sequences for the pre-prohormones and guanylate cyclase isoforms had structural features in common with sequences previously reported for guanylin-like peptides and guanylate cyclases from teleost fish and other species in general. The highest sequence homologies for the prohormones were found within the active, 15-16 amino acid C-terminal peptide domain, whereas the guanylate cyclase receptors exhibited highest homology throughout the transmembrane domain and intracellular region of the protein comprising the kinase homology, oligomerisation/coiled-coil and catalytic domains. In both yellow and silver eels, seawater (SW) acclimation induced sustained increases in the expression of uroguanylin and GC-C1 mRNAs within the intestine but no significant changes were found in the abundance of mRNAs for guanylin, renoguanylin or GC-C2. Likewise there were no significant changes in expression of any of the prohormone or receptor mRNAs within the renal kidney following transfer to SW. The results suggest that uroguanylin and GC-C1 are key components of a cGMP signalling system that may play an important role within intestinal enterocytes for the regulation of salt and water absorption in the SW-acclimated eel.
 ...
PMID:Guanylin-like peptides, guanylate cyclase and osmoregulation in the European eel (Anguilla anguilla). 1902 95