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)

A set of inhibitors including hematin, bromosulfophthalein, and triethyltin bromide was used for discrimination and identification of the major basic isozymes of glutathione transferase in rat liver cytosol. Six enzymes are formed as binary combinations of 4 protein subunits: A, B, C, and L. Discrimination between the transferases can be based on the differences of the subunits in susceptibility to the inhibitors. The identification of transferase subunits is further supported by the combined use of specific substrates and inhibitors.
...
PMID:A set of inhibitors for discrimination between the basic isozymes of glutathione transferase in rat liver. 688 56

The P2 porin protein is the major outer membrane protein of nontypeable Haemophilus influenzae and is a potential target of a protective immune response. Nine monoclonal antibodies (MAbs) to P2 were developed by immunizing mice with nontypeable H. influenzae whole organisms. Each MAb reacted exclusively with the homologous strain in a whole-cell immunodot assay demonstrating exquisite strain specificity. All nine MAbs recognized abundantly expressed surface-exposed epitopes on the intact bacterium by immunofluorescence and immunoelectron microscopy. Each MAb was bactericidal to the homologous strain in an in vitro complement-mediated killing assay. Immunoblot assay of cyanogen bromide cleavage products of purified P2 indicated that MAb 5F2 recognized the 10-kDa fragment, and the other eight MAbs recognized the 32-kDa fragment. Competitive ELISAs confirmed that 5F2 recognized an epitope that is different from the other eight MAbs. To further localize epitopes, MAbs 5F2 and 6G3 were studied in protein footprinting by using reversed-phase high-performance liquid chromatography. Three potential epitope-containing peptides which were reactive in an enzyme-linked immunosorbent assay with both 5F2 and 6G3 were isolated. These peptides were identified by N-terminal amino acid sequence and localized to loops 5 and 8 of the proposed model for P2. Fusion proteins consisting of glutathione S-transferase fused with variable-length peptides from loops 5 and 8 were expressed in the pGEX-2T vector. Immunoblot assay of fusion peptides of loops 5 and 8 confirmed that 5F2 recognized an epitope within residues 338 to 354 of loop 8; 6G3 and the remaining MAbs recognized an epitope within residues 213 to 229 of loop 5. These studies indicate that nontypeable H. influenzae contains bactericidal epitopes which have been mapped to two different surface-exposed loops of the P2 molecule. These potentially protective epitopes are strain specific and abundantly expressed on the surface of the intact bacterium.
...
PMID:Mapping of bactericidal epitopes on the P2 porin protein of nontypeable Haemophilus influenzae. 752 Apr 20

We expressed the carboxyl-terminal 178 amino acids of the rabbit cardiac Na+/H+ exchanger as a fusion protein with glutathione-S-transferase. The fusion protein (PCR178) was found in the supernatant of extracts of E. coli and was purified using Glutathione-Sepharose affinity chromatography. Affinity-purified antibodies raised against the carboxyl-terminal region of the Na+/H+ exchanger identified the resultant protein. PCR178 copurified with a 70 kDa protein. Amino-terminal sequencing of the 70 kDa protein identified it as dnaK, the bacterial equivalent of the mammalian 70 kDa heat shock protein (hsp70). DnaK was dissociated from the Na+/H+ exchanger fusion protein by the addition of MgATP. When purified PCR178 was coupled to a cyanogen bromide-activated Sepharose column, bovine hsp70 bound to the column and was eluted with MgATP. Nondenaturing polyacrylamide gel electrophoresis showed that, in the absence of MgATP, hsp70 formed a complex with PCR178. The complex was dissociated by the addition of MgATP. GST alone did not form a complex with hsp70. Immunoprecipitation of the Na+/H+ exchanger with antiexchanger antibodies resulted in coprecipitation of hsp70 protein from antiporter containing cells. Cells that overexpress the Na+/H+ exchanger had increased amounts of hsp70 which coprecipitated with antiexchanger antibody. The results show that heat shock protein complexes with the mammalian Na+/H+ exchanger.
...
PMID:The carboxyl-terminal region of the Na+/H+ exchanger interacts with mammalian heat shock protein. 765 95

We examined whether inhibitors of the arachidonic acid cascade inhibited nitric oxide (NO) production, as measured by nitrite concentration, either in macrophages or by their cytosolic fractions. Nitrite production by peritoneal macrophages from mice receiving OK-432 treatment was significantly inhibited by phospholipase A2 inhibitors [dexamethasone and 4-bromophenacyl bromide (4-BPB)], lipoxygenase inhibitors [nordihydroguaiaretic acid (NDGA) and ketoconazole] and a glutathione S-transferase (leukotrienes LTA4-LTC4) inhibitor (ethacrynic acid). However, caffeic acid and esculetin, inhibitors of 5- and 12-lipoxygenase respectively, were not inhibitory. On the other hand, indomethacin, a cyclooxygenase inhibitor, slightly inhibited whereas another inhibitor, ibuprofen, did not. Inhibition of the nitrite production by dexamethasone, 4-BPB, NDGA and ethacrynic acid was also demonstrated when the macrophages were restimulated ex vivo with OK-432 or with lipopolysaccharide. The inhibitory activity of dexamethasone, NDGA and ethacrynic acid was significantly reduced by ex vivo restimulation with OK-432, whereas that of 4-BPB was hardly affected. Furthermore, the inhibitory activity of dexamethasone, NDGA and ethacrynic acid was much higher when the macrophages were continuously exposed to the agents than when they were pulsed. Meanwhile, inhibition by 4-BPB was almost the same with either treatment. In addition, the inhibitory activity of these agents was not blocked with L-arginine, a substrate of NO synthases, or with arachidonate metabolites (LTB4, LTC4 and LTE4). Ethacrynic acid and 4-BPB, but not dexamethasone and NDGA, also inhibited nitrite production by the cytosolic fractions from OK-432-restimulated peritoneal macrophages, and the inhibitory activity of 4-BPB was superior to that of ethacrynic acid. These agents, however, did not inhibit nitrite production from sodium nitroprusside, a spontaneous NO-releasing compound. These results indicate that dexamethasone, 4-BPB, NDGA and ethacrynic acid inhibited the production of NO by macrophages through at least two different mechanisms: one was inhibited by dexamethasone, NDGA and ethacrynic acid and the other by 4-BPB. Furthermore, 4-BPB and ethacrynic acid directly inhibited the activity of the NO synthase in macrophages, suggesting that the agents work by binding to the active site(s) of the enzyme.
...
PMID:Inhibition of macrophage nitric oxide production by arachidonate-cascade inhibitors. 769 96

A mu-class glutathione S-transferase (GST) cDNA clone, pHMB1, from rabbit liver has been constructed, using a 748-base-pair fragment of GST Yb1 cDNA as a probe. The nucleotide sequence of pHMB1 has been determined, and the complete amino acid sequence has been deduced. Recombinant clone pHMB1 contains a cDNA insert of 1443 base pairs with 654 nucleotides of open reading frame, 33 nucleotides of 5'-untranslated region, and 756 nucleotides of 3'-untranslated region. The open reading frame encodes a polypeptide (rbGST mu I) comprising 218 amino acids with molecular weight of 25,417. Compared to published mu-class GST sequences, rbGST mu I is 73 and 77% identical to rat Yb1 and human GST4 in amino acid sequence, respectively. The pHMB1 was expressed in Escherichia coli using expression vector pIH821 and the expressed GST was purified as a single band on polyacrylamide gel electrophoresis by maltose- and glutathione-affinity column chromatography. Rabbit liver GST protein expressed by this system was catalytically active. The functional characterization was done on the expressed protein. The rabbit liver GST expressed in E. coli showed greater activity toward 1,2-dichloro-4-nitrobenzene than mu-class isozymes in rabbit hepatic tissue (T. Primiano and R.F. Novak (1993) Arch. Biochem. Biophys. 301, 404-410). Enzymatic activity of expressed protein toward the substrate 1-chloro-2,4-dinitrobenzene was inhibited by triethyltin bromide, Cibacron blue, triphenyltin chloride, bromosulfophthalein, and hematin. RNA blot hybridization demonstrated that the pHMB1 mRNA was well expressed in rabbit liver, brain, and kidney.
...
PMID:Cloning and expression of a cDNA for mu-class glutathione S-transferase from rabbit liver. 773 73

We previously found that human cervix carcinoma HeLa cells irradiated with multiple fractions of gamma rays (0.5 Gy daily, five times per week over 6 weeks) become resistant to cis-dichlorodiammineplatinum(II) (cis-DDP), methotrexate (MTX) and vincristine (VCR), but retain the same sensitivity to gamma rays or UV light. In the present report attempts were made to elucidate the mechanisms by which these cells have acquired resistance to cis-DDP and VCR. The sensitivity to different drugs was measured by modified MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. Neither buthionine sulfoximine (BSO) nor ethacrinic acid were able to reverse the resistance of preirradiated cells to cis-DDP. Therefore, neither the increased levels of glutathione nor glutathione transferase seem to be involved in resistance to cis-DDP. Preirradiated cells did show resistance to cadmium, indicating the increased levels of metallothioneins in these cells. Resistance of preirradiated cells to vincristine was abolished by the addition of verapamil, indicating that resistance to this drug may depend on the increased expression of plasma membrane P-glycoprotein. It was concluded that mechanisms of resistance of preirradiated cells to cytostatics are multifactorial and involve at least the increased levels of metallothioneins and changes in the plasma membrane. Acquired resistance to cytotoxic drugs induced by preirradiation may be the reason for the reduced response to these drugs after radiation treatment of certain tumors.
...
PMID:Multifactorial molecular mechanisms are involved in resistance of preirradiated human cervix carcinoma cells to cis-dichlorodiammineplatinum (II) and vincristine. 810 78

A novel glutathione S-transferase (GST) was purified from broccoli (Brassica oleracea var. italica). Partial amino-acid sequencing indicated that the protein shared significant homology with several different plant GSTs from maize, silene, Dianthus, Nicotiana and Triticum, but little homology to yeast (Issatchenkia) GST. One region of the polypeptide near the N-terminal also shared significant homology to a region of rat 5-5, rat 12-12 and human theta-GST (collectively referred to as the theta-GST-class) but little structural homology to the common mammalian cytosolic GSTs (alpha-, mu- or pi-classes). The broccoli GST was retained on a novel membrane based glutathione affinity matrix and displayed activity towards 1-chloro-2,4-dinitro-benzene (CDNB), a general GST substrate, as well as 4-nitrophenethyl bromide, a marker substrate for the theta-class of GSTs. The characteristics of the broccoli GST potentially define it as a member of the theta-class. This is consistent with the view that the theta-class may have arisen prior to the divergence of animals and plants while the mammalian mu-, pi- and alpha-classes evolved after the two kingdoms were established.
...
PMID:A glutathione S-transferase (GST) isozyme from broccoli with significant sequence homology to the mammalian theta-class of GSTs. 814 81

Class mu glutathione S-transferases (GSTs) are important in the detoxication of epoxides generated by oxidative metabolism. Phenobarbital, 3-methylcholanthrene, and pyridine have failed to enhance the expression of class mu GST isozymes in rabbit hepatic tissue (T. Primiano, S. G. Kim, and R. F. Novak, Toxicol. Appl. Pharmacol., 113, 64-73, 1992). Two class mu GST isozymes have been isolated from rabbit hepatic cytosol and purified to homogeneity using S-hexylglutathione-agarose, CM-Sepharose, and PBE94 chromatofocusing chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analyses showed that both isozymes possessed M(r) values of approximately 25,500 and cross-reacted with class mu-specific GST IgG. Gel filtration analysis revealed that these isozymes were dimers with molecular weights of approximately 45 kDa. The class mu GST isozymes had pIs of 7.8 and 7.2 as determined by nonequilibrium pH gel electrophoresis. The class mu GST 7.8 and 7.2 isozymes exhibited different metabolic activities toward the substrates 1-chloro-2,4-dinitrobenzene, bromosulfophthalein, 1,2-epoxy-3-(p-nitrophenoxy)propane, trans-4-phenyl-3-buten-2-one, p-nitrobenzyl chloride, and 3,4-dichloronitrobenzene. Metabolic activity of the two GSTs toward the substrate 1-chloro-2,4-dinitrobenzene was inhibited by Cibacron blue, triethyltin bromide, S-hexylglutathione, bromosulfophthalein, and indomethacin. The amino acid composition of GST mu 7.8 and 7.2 was determined and found to be very similar to those of purified rat class mu GST isozymes. N-terminal analysis of the first 21 residues of the pI 7.8 class mu GST isozyme revealed that it had 71 and 81% sequence identity with the Yb1 and Yb2 subunits, respectively. Similarly, N-terminal analysis of the first 21 residues of the pI 7.2 class mu GST isozyme revealed a 75% sequence identity with either the rat Yb1 or Yb2 subunit. Examination of class mu GST expression in rabbit hepatic cytosol following treatment with a series of known inducers including phenobarbital, 3-methylcholanthrene, isosafrole, pyrazine, trans-stilbene oxide, butylated hydroxyanisole, and tert-butylhydroquinone was accomplished. The data show that these agents not only failed to enhance class mu GST expression, but that 3-methylcholanthrene and isosafrole caused suppression of class mu GSTs. These results provide evidence for the existence of two closely related class mu GST isozymes in rabbit hepatic tissue and suggest that the molecular mechanisms regulating GST expression differ between rat and rabbit in response to these xenobiotics.
...
PMID:Purification and characterization of class mu glutathione S-transferase isozymes from rabbit hepatic tissue. 846 Sep 49

Histatin 1 is a histidine-rich phosphoprotein present in human parotid saliva that possesses candidacidal activity and functions in mineralization by adsorbing to hydroxyapatite. The objective of the present study was to develop a system for recombinant production of histatin 1 and to examine the role of phosphorylation in the functional activities of this molecule. Native histatin 1 (containing a phosphoserine at residue 2) was purified from parotid saliva, whereas a bacterial expression system was used to produce a recombinant form of histatin 1 (re-Hst1) that lacked phosphorylated serine. Histatin 1 cDNA was inserted into the vector pGEX-3X, which expresses foreign genes as soluble fusion proteins attached to the carboxyl-terminus of glutathione S-transferase (GST). The GST/re-Hst1 fusion protein was isolated from cell lysates by affinity chromatography on glutathione (GSH)-Sepharose and digested with cyanogen bromide to separate re-Hst1 from the GST fusion partner. The digest was subjected to reversed-phase high-performance liquid chromatography on a C18 column, and re-Hst1 was eluted as a well-defined peak. The yield of re-Hst1 was 4 mg/L of bacterial culture. Amino-terminal sequencing and amino acid analysis confirmed the final product as re-Hst1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that native histatin 1 and re-Hst1 had the same apparent molecular weights, while cationic PAGE showed that re-Hst1 was more basic. Phosphate analysis indicated 1 mol phosphate/mol of native histatin 1, while re-Hst1 lacked any detectable phosphate. Re-Hst1 demonstrated candidacidal activity comparable to that of native histatin 1, but displayed substantially lower binding to hydroxyapatite. These results show that phosphorylation of histatin 1 at residue 2 contributes significantly to its ability to bind to hydroxyapatite.
...
PMID:Functional comparison of native and recombinant human salivary histatin 1. 860 Jan 79

2-Hydroxy-5-nitrobenzyl alcohol (HNB) was prepared from dimethyl(2-hydroxyl-5-nitrobenzyl)sulfonium bromide (HNBB). HNB binds to glutathione S-transferases (GSTs) 1-2 and 2-2 with moderate affinity at a site separate from 1-anilino-8-naphthalenesulfonate (ANS). Intrinsic fluorescence due to Trp-21 is strongly quenched by HNB binding but there is no effect on catalytic activity. There appear to be two HNB binding sites per dimer in each GST isoenzyme. We suggest that HNB binds directly at Trp-21 of each subunit and that previously reported quenching of intrinsic fluorescence in these proteins upon ligand binding may be due to indirect structural effects rather than direct binding at this residue.
...
PMID:Binding of 2-hydroxy-5-nitrobenzyl alcohol to rat alpha class glutathione S-transferases; evidence for binding at tryptophan 21. 862 28


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

---