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

---

Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spontaneous release of nitric oxide (NO) from S-nitrosothiols cannot explain their bioactivity, suggesting a role for cellular metabolism or receptors. Using immortalised cells and human platelets, we have identified a cell-mediated mechanism for the biotransformation of the physiological S-nitrosothiol compound S-nitrosoglutathione (GSNO) into nitrite. We suggest the name "GSNO lyase" for this activity. GSNO lyase activity varied between cell types, being highest in a fibroblast cell line and lowest in platelets. In NRK 49F fibroblasts, GSNO lyase mediated a saturable, GSNO concentration-dependent accumulation of nitrite in conditioned medium, which was inhibited both by transition metal chelators, and by subjecting cells to oxidative stress using a combination of the thiol oxidant diamide and Zn2+, a glutathione reductase inhibitor. Activity was resistant, however, to both acivicin, an inhibitor of gamma-glutamyl transpeptidase (EC 2.3.2.2), and to ethacrynic acid, an inhibitor of Pi class glutathione-S-transferases (EC 2.5.1.18), thus neither of these enzymes could account for NO release. Although GSNO lyase does not explain the platelet-selective pharmacological properties of GSNO, cellular biotransformation suggests therapeutic avenues for targeted delivery of NO to other tissues.
...
PMID:Cell-mediated biotransformation of S-nitrosoglutathione. 951 76

A snake venom-like protease isolated by a differential display screen between normal and osteoarthritis (OA)-affected cartilage (designated as cSVP) has a cDNA sequence identical to TNF-alpha convertase enzyme (TACE). TACE shows the presence of an unknown prodomain, a cysteine switch, a catalytic domain, a zinc binding region, a disintegrin region, an EGF-like domain, a transmembrane domain, and a unique cytoplasmic region. A TACE construct harboring the signal + prodomain + catalytic region (TACE-SPCdeltaDETCy), expressed in baculovirus could cleave preferentially (approximately 12-fold) the TNF-specific peptide over the matrix metalloproteases peptide in vitro. This recombinant protein also cleaved the natural substrate GST-ProTNF-alpha to TNF-alpha (17 kDa) in vitro. The mRNA for TACE, which is broadly distributed and differentially expressed in a variety of human tissues, is up-regulated in arthritis-affected cartilage, but not normal cartilage. OA-affected cartilage also expressed TNF-alpha mRNA that was not detected in normal cartilage. The OA-affected cartilage (in explant assays) spontaneously released TNF-alpha and IL-8 in ex vivo conditions. Addition of TNF-alphaR fused to IgG Fc fragment (TNF-alphaR:Fc) in the presence or absence of soluble IL-1R (with which it acted additively) significantly attenuated the spontaneous/autocrine release of articular IL-8 in this assay. These experiments demonstrate a functional paracrine/autocrine role of TNF-alpha in OA-affected cartilage that may depend, in part, on up-regulated levels of chondrocyte-derived TACE.
...
PMID:TNF-alpha convertase enzyme from human arthritis-affected cartilage: isolation of cDNA by differential display, expression of the active enzyme, and regulation of TNF-alpha. 957 64

Sequence analysis of the downstream region of the basidiomycete Lentinus edodes priB gene encoding a protein with a 'Zn(II)2Cys6 zinc cluster' DNA-binding motif (Endo, H., Kajiwara, S., Tunoka, O., Shishido, K., 1994. A novel cDNA, priBc, encoding a protein with a Zn(II)2Cys6 zinc cluster DNA-binding motif, derived from the basidiomycete Lentinus edodes. Gene 139, 117-121) suggested the presence of a Saccharomyces cerevisiae URA6 gene homologue encoding UMP kinase. We isolated a corresponding cDNA from a mature fruiting-body cDNA library of L. edodes. The nucleotide sequence of this was determined and compared with that of the genomic DNA, revealing that the URA6 gene homologue encodes 227 amino acids (aa) and is interrupted by four small introns. The deduced aa sequence showed an overall identity of 51.1% to that of the S. cerevisiae URA6 gene product. The URA6 homologue protein produced in Escherichia coli using the glutathione S-transferase gene fusion system was found to catalyze the phosphoryl transfer from ATP to UMP and CMP efficiently and also to AMP and dCMP with lower efficiencies. Thus, the URA6 gene homologue was designated uck1 and its product UMP-CMP kinase. Northern-blot analysis showed that the uck1 is actively transcribed in the gill tissue of mature fruiting bodies of L. edodes, implying that uck1 may play a role during the formation of basidiospores occurs in the gill tissue.
...
PMID:Cloning, sequence analysis and expression of the basidiomycete Lentinus edodes gene uck1, encoding UMP-CMP kinase, the homologue of Saccharomyces cerevisae URA6 gene. 960 45

pICln is a ubiquitous cellular protein that has been proposed to be a volume-sensitive Cl- channel or a channel regulator. Detailed biochemical, cellular and molecular characterization of pICln is required to understand its function. Our goal in the present investigation was to define further the biochemical properties of pICln and the proteins that associate with it. Immunoprecipitation of pICln from 32P-orthophosphoric acid-labeled C6 glioma cells revealed that the protein is phosphorylated constitutively, primarily on serine residues. Protein kinase activity was detected in pICln immunoprecipitates, revealing that a constitutively active protein kinase co-precipitates with pICln. A specific association between pICln and a protein kinase was also observed in affinity assays using a recombinant GST-pICln fusion protein. The pICln-associated kinase displayed broad substrate specificity and was inhibited in a concentration-dependent manner by heparin, zinc and 5,6-dichloro-1-beta-D-ribofuranosylbenose (DRB). These characteristics resembled those of casein kinase I and II. The pICln-associated kinase was not recognized, however, by antibodies against these two enzymes. Association of the kinase with pICln was disrupted by increasing concentrations of NaCl in the washing buffer, suggesting that electrostatic interactions are involved in kinase binding. Mutagenesis experiments corroborated this observation. Truncation of pICln demonstrated that two highly charged clusters of acidic amino acid residues are both necessary and sufficient for kinase binding. Phosphopeptide mapping demonstrated that pICln contains at least two phosphorylated serine residues that are located on trypsin cleavage fragments rich in acidic amino acid residues. We propose that the kinase or a kinase binding protein binds to acidic amino acids located between D101 and Y156 and phosphorylates nearby serine residues.
...
PMID:Characterization of pICln phosphorylation state and a pICln-associated protein kinase. 965 71

Two month-old Wistar male albino rats were exposed during a 30-day period to a daily oral intake ad libitum of either 200 microg/mL Cd (as CdCl2), 0.1 microg/mL Se (as Na-selenite), or the same dosages of Cd + Se in drinking water. The daily intake from the water was calculated to be 15 mg Cd/kg and 7 microg Se/kg. Cadmium (Cd) accumulates in the heart (p < 0.005) and, in rats, decreases both body mass growth (p < 0.005) and heart mass (p < 0.02). Selenium (Se) significantly decreases the negative effect of Cd on body mass growth. In the hearts of Cd-treated rats, cadmium caused the decrease (p < 0.05) of selenium-dependent glutathione peroxidase (GSH-Px, EC 1.11.1.9) activity. At the same time, the activities of total superoxide dismutase (total SOD, EC 1.15.1.1), manganese-containing superoxide dismutase (Mn SOD), and copper-zinc-containing superoxide dismutase (CuZn SOD) were increased (p < 0.005). The activities of total SOD, CuZn SOD (p < 0.005), GSH-Px (p < 0.02), and glutathione-S-transferase (GST, p < 0.005) were increased in the hearts of Se-treated rats. However, by concomitant administration of Cd and Se, these changes were diminished (total SOD, GST) or were completely eliminated (Mn SOD, GSH-Px). These results indicate that Se only partly diminishes the effects of Cd cardiotoxicity.
...
PMID:The effect of cadmium and selenium on the antioxidant enzyme activities in rat heart. 972 99

Specific oxidative metabolites of valproic acid (VPA) have been associated with the clinically defined toxicity of the drug. To investigate the role of enzymatic detoxification in clinical toxicity, we compared activities of five antioxidant enzymes in 15 patients with a serious adverse experience (SAE) related to VPA therapy, to enzyme activities measured in 35 patients with good clinical tolerance of VPA, and 50 healthy, age-matched subjects. These enzymes included glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione transferase, superoxide dismutase, and catalase in erythrocytes; and GSH-Px in plasma. We also determined levels of Se, Cu, and Zn, trace elemental cofactors for these enzymes, in plasma from each individual. In patients with a VPA-associated SAE, GSH-Px was significantly depressed and GSSG-R was significantly elevated relative to values for the other groups. Selenium and zinc concentrations were lower in SAE patients than in controls. These findings may indicate a role for selenium dependent antioxidant activity in individual susceptibility to an SAE related to VPA therapy.
...
PMID:Altered antioxidant enzyme activities in children with a serious adverse experience related to valproic acid therapy. 976 95

Sensors based on proteins (GST-SmtA and MerR) with distinct binding sites for heavy metal ions were developed and characterized. A capacitive signal transducer was used to measure the conformational change following binding. The proteins were overexpressed in Escherichia coli, purified, and immobilized in different ways to a self-assembled thiol layer on a gold electrode placed as the working electrode in a potentiostatic arrangement in a flow analysis system. The selectivity and the sensitivity of the two protein-based biosensors were measured and compared for copper, cadmium, mercury, and zinc ions. The GST-SmtA electrodes displayed a broader selectivity (sensing all four heavy metal ions) compared with the MerR-based ones, which showed an accentuated selectivity for mercury ions. Metal ions could be detected with both electrode types down to femtomolar concentration. The upper measuring limits, presumably due to near saturation of the proteins' binding sites, were around 10(-10) M. Control electrodes similarly constructed but based on bovine serum albumin or urease did not yield any signals. The electrodes could be regenerated with EDTA and used for more than 2 weeks with about 40% reduction in sensitivity.
...
PMID:Detection of heavy metal ions at femtomolar levels using protein-based biosensors. 978 52

Binding of the protein tyrosine kinase p56(lck) to T-cell co-receptors CD4 and CD8alpha is necessary for T-lymphocyte development and activation. Association of p56(lck) with CD4 requires two conserved cysteine residues in the cytosolic domain of CD4 and two in the amino terminus of p56(lck), consistent with the notion that these four residues coordinate a single metal atom (1-5). Here we demonstrate that Zn2+ is essential for complex formation. In an in vitro binding reaction, Zn2+ mediates p56(lck) association with a glutathione S-transferase (GST) fusion protein containing the cytosolic domains of CD4 or CD8alpha; no other metals tested support binding. Treatment of preformed GST-CD4.p56(lck) dimers with the Zn2+ chelators 1,10-O-phenanthroline or 8-hydroxyquinoline-5-sulfonic acid results in dissociation of GST-CD4 from p56(lck), consistent with the finding of Huse et al. (5) that Zn2+ is contained within similar complexes. Furthermore, we show that, within live cells, CD4.p56(lck) and CD8alpha.p56(lck) interactions occur in a zinc-dependent fashion. Specifically, pretreatment of the human Jurkat T-cell line with membrane permeable zinc chelators disrupts CD4.p56(lck) complexes, and treatment of COS cells co-expressing CD8alpha and p56(lck) with such chelators likewise leads to dissociation of CD8alpha.p56(lck) complexes. CD4. p56(lck) and CD8alpha.p56(lck) represent the first examples of intracellular proteins that require zinc as a bridge for heterodimerization.
...
PMID:Zinc is essential for binding of p56(lck) to CD4 and CD8alpha. 983 36

Recombinant murine MRP14 (mMRP14) was produced in Escherichia coli using the pGEX expression system. The mass of fusion protein, by electrospray ionization-mass spectrometry (ESI/MS), was 39,213 Da which compares well with the theoretical mass (39,210.4 Da). Thrombin digestion of fusion protein was expected at a cloned thrombin consensus sequence (. LVPRGS. ) located between glutathione S-transferase and mMRP14. Analysis of products of digestion by C4 reverse-phase HPLC and SDS-PAGE/Western blotting revealed two immunoreactive cleavage products with molecular weights around 13, 000. Masses of the two proteins determined by ESI/MS were 13,062 and 11,919 Da. The larger product corresponded to the expected mass of recombinant mMRP14 (13,061.9 Da). Analysis of the protein sequence of recombinant mMRP14 revealed a thrombin-like consensus sequence (. NNPRGH. ) located close to the C-terminus. The smaller protein corresponded to a truncated form of rec mMRP14 (rec MRP141-102) with a calculated mass of 11,918.6 Da. Optimization of the cleavage conditions resulted in >95% full-length rec mMRP14. Native mMRP14 contains one intramolecular disulfide bond between Cys79 and Cys90. The full-length recombinant protein was renatured and oxidized in ammonium acetate (pH approximately 7) for 96 h and formed >95% of the native intramolecular disulfide-bonded form. MRP141-102 bound substantially less 65Zn2+ compared to native mMRP14 or rec mMRP14 after transfer to polyvinylidene difluoride and incubation with 65ZnCl2, implicating the His residues located within the C-terminal domain in Zn2+ binding.
...
PMID:Overexpression, oxidative refolding, and zinc binding of recombinant forms of the murine S100 protein MRP14 (S100A9). 1004 80

Human cytokeratin 1 (CK1) in human umbilical vein endothelial cells (HUVEC) is expressed on their membranes and is able to bind high molecular weight kininogen (HK) (Hasan, A. A. K., Zisman, T., and Schmaier, A. H. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 3615-3620). New investigations have been performed to demonstrate the HK binding domain on CK1. Four overlapping recombinant (r) CK1 proteins were produced in Escherichia coli by a glutathione S-transferase gene fusion system. Biotin-HK specifically bound to rCK128 and rCK131 in the presence of Zn2+ but not to Deleted1-6rCK131. Recombinant CK128 and rCK131 also inhibited biotin-HK binding to HUVEC with IC50 of 0.4 and 0.5 microM, respectively. Alternatively, rCK114 and Deleted1-6rCK131 did not inhibit binding at concentrations >/=1 microM. Seven sequential 20 amino acid peptides of CK1 were prepared to cover the protein coded by exons 1-3. Only the first peptide (GYG20) coded by exon 1 significantly inhibited HK binding to HUVEC with an IC50 of 35 microM. Fine mapping studies isolated two overlapping peptides also coded by exon 1 (GPV15 and PGG15) that inhibited binding to HUVEC with IC50 of 18 and 9 microM, respectively. A sequence scrambled peptide of PGG15 did not block binding to HUVEC and biotin-GPV20 specifically bound to HK. Peptides GPV15 and PGG15 also blocked prekallikrein activation on endothelial cells. However, inhibition of PK activation by peptide PGG15 occurred at 10-fold lower concentration (IC50 = 1 microM) than inhibition of biotin-HK binding to HUVEC (IC50 = 10 microM). These studies indicate that HK binds to a region of 20 amino acids coded by exon 1 on CK1 which is carboxyl-terminal to its glycine-rich amino-terminal globular domain. Furthermore, HK binding to CK1 modulates PK activation on HUVEC.
...
PMID:Mapping binding domains of kininogens on endothelial cell cytokeratin 1. 1006 72


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---