Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA polymerase epsilon (Pol epsilon) is a multi-subunit enzyme required for the initiation of chromosomal DNA replication. Here, we report the cloning of two fission yeast genes, called dpb3+ and dpb4+ that encode proteins homologous to the two smallest subunits of Pol epsilon. Although Dpb4 is not required for cell viability, Deltadpb4 mutants are synthetically lethal with mutations in four genes required for DNA replication initiation, cdc20+ (encoding DNA Pol epsilon), cut5+ (homologous to DPB11/TopBP1), sna41+ (homologous to CDC45) and cdc21+ (encoding Mcm4, a component of the pre-replicative complex). In contrast to Dpb4, Dpb3 is essential for cell cycle progression. A glutathione S-transferase pull-down assay indicates that Dpb3 physically interacts with both Dpb2 and Dpb4, suggesting that Dpb3 associates with other members of the Pol epsilon complex. Depletion of Dpb3 leads to an accumulation of cells in S phase consistent with Dpb3 having a role in DNA replication. In addition, many of the cells have a bi-nucleate or multinucleate phenotype, indicating that cell separation is also inhibited. Finally, we have examined in vivo localization of green fluorescent protein (GFP)-tagged Dpb3 and Dpb4 and found that both proteins are localized to the nucleus consistent with their proposed role in DNA replication. However, in the absence of Dpb3, GFP-Dpb4 appears to be more dispersed throughout the cell, suggesting that Dpb3 may be important in establishing or maintaining normal localization of Dpb4.
 ...
PMID:Identification and cloning of two putative subunits of DNA polymerase epsilon in fission yeast. 1538 3

Epirubicin HCl is a new anthracycline analog and derivative of doxorubicin. Doxorubicin is a potent anticancer agent, the use of which is limited by its cumulative dose-dependent cardiotoxicity. Epirubicin HCl has more favorable therapeutic index than doxorubicin and possesses less hematologic and cardiac toxicity at comparable doses. Hepatoma G2 cells are a valuable model to study hepatocellular carcinoma and the liver, where drugs are metabolized. The goal of our study was to evaluate the cytotoxic effect of epirubicin HCl on viability of Hep G2 cells measured using the MTT cytotoxicity test. Epirubicin HCl produced a concentration- and time-dependent cytotoxicity to Hep G2 cells. The mechanism of cytotoxicity of epirubicin HCl (IC(50) value of 1.6 mug/ml within 24 h) appeared to involve a production of free radical species since activities of free radical scavenging enzymes (SOD, catalase, Se-dependent GPx) were increased. Addition of SOD prevented cytotoxicity of epirubicin HCl, and also counteracted the apoptosis. DNA fragmentation was determined to evaluate apoptosis. Western blot analysis indicated a decrease in GST-pi expression and increased activity of NADPH-dependent cytochrome P450 reductase which is a major enzyme in the conversion of epirubicin HCl to a free radical. It is proposed that production of reactive oxygen species increased by the treatment with epirubicin HCl can cause lipid peroxidation, which subsequently promotes apoptosis and reduces cell viability. Superoxide dismutase, catalase and glutathione peroxidase must be considered as a part of the intracellular antioxidant defense mechanism of Hep G2 cells against single electron reducing quinone-containing anticancer antibiotics.
Pol J Pharmacol
PMID:Epirubicin HCl toxicity in human-liver derived hepatoma G2 cells. 1552 Apr 98

We recently determined the ORF1 cleavage map of Mc10, a human sapovirus (SaV) strain, as follows: NH2-p11-p28-p35(NTPase)-p32-p14(VPg)-p70(Pro-Pol)-p60(VP1)-COOH. This cleavage was dependent on the viral encoded 3C-like protease. To identify the cleavage site of SaV ORF1, putative p70 (Pro-Pol) and p14-p70 (VPg-Pro-Pol) were expressed as N-terminal GST and C-terminal 6 x His-tag fusion proteins in Escherichia coli, and the expressed products were analyzed by SDS-PAGE and Western blotting. Our results indicated that the efficient proteolytic cleavage occurred between p14 (VPg) and p70 (Pro-Pol), and N-terminal amino acid sequencing revealed that the cleavage site was between E(1055) and A(1056). In contrast, the p70 (Pro-Pol) was not further cleaved. We also found that SaV protease cleaved the Q/G site within the rhinovirus 3C protease recognition site. Site-directed mutagenesis in a conserved GDCG motif of the protease completely abolished these proteolytic activities. This is the first report to identify the cleavage site of the SaV ORF1 polyprotein.
 ...
PMID:Cleavage activity of the sapovirus 3C-like protease in Escherichia coli. 1605 86

An intracellular glutathione transferase was purified to homogenity from the fungus, Mucor mucedo, using DEAE-cellulose ion-exchange and glutathione affinity chromatography. Gel filtration chromatography and SDS-PAGE revealed that the purified GST is a homodimer with approximate native and subunit molecular mass of 53 kDa and 23.4 kDa, respectively. The enzyme has a pI value of 4.8, a pH optimum at pH 8.0 and apparent activation energy (Ea) of 1.42 kcal mol(-1). The purified GST acts readily on CDNB with almost negligible peroxidase activity and the activity was inhibited by Cibacron Blue (IC50 0.252 microM) and hematin (IC50 3.55 microM). M. mucedo GST displayed a non-Michaelian behavior. At low (0.1-0.3 mM) and high (0.3-2 mM) substrate concentration, Km (GSH) was calculated to be 0.179 and 0.65 mM, whereas Km(CDNB) was 0.531 and 11 mM and k(cat) was 39.8 and 552 s(-1), respectively. The enzyme showed apparent pKa values of 6-6.5 and 8.0.
Pol J Microbiol 2005
PMID:Purification and characterization of a glutathione S-transferase from Mucor mucedo. 1620 9

We investigated glutathione level, activities of selenium independent GSH peroxidase, selenium dependent GSH peroxidase, GSH S-transferase, GSH reductase and the rate of lipid peroxidation expressed as the level of malondialdehyde in liver tissues obtained from patients diagnosed with cirrhosis or hepatocellular carcinoma. GSH level was found to be lower in malignant tissues compared to adjacent normal tissues and it was higher in cancer than in cirrhotic tissue. Non-Se-GSH-Px activity was lower in cancer tissue compared with adjacent normal liver or cirrhotic tissue, while Se-GSH-Px activity in cancer was found to be similar to its activity in cirrhotic tissue and lower compared to control tissue. An increase in GST activity was observed in cirrhotic tissue compared with cancer tissue, whereas the GST activity in cancer was lower than in adjacent normal tissue. The activity of GSH-R was similar in cirrhotic and cancer tissues, but higher in cancer tissue compared to control liver tissue. An increased level of MDA was found in cancer tissue in comparison with control tissue, besides its level was higher in cancer tissue than in cirrhotic tissue. Our results show that the antioxidant system of cirrhosis and hepatocellular carcinoma is severely impaired. This is associated with changes of glutathione level and activities of GSH-dependent enzymes in liver tissue. GSH and enzymes cooperating with it are important factors in the process of liver diseases development.
Acta Biochim Pol 2006
PMID:Glutathione and GSH-dependent enzymes in patients with liver cirrhosis and hepatocellular carcinoma. 1640 76

Human glutathione S-transferase omega 1-1 (hGSTO1-1) is a newly identified member of the glutathione S-transferase (GST) family of genes, which also contains alpha, mu, pi, sigma, theta, and zeta members. hGSTO1-1 catalyzes the reduction of arsenate, monomethylarsenate (MMA(V)), and dimethylarsenate (DMA(V)) and exhibits thioltransferase and dehydroascorbate reductase activities. Recent evidence has show that cytokine release inhibitory drugs, which specifically inhibit interleukin-1b (IL-1b), directly target hGSTO1-1. We found that (+)-alpha-tocopherol phosphate and (+)-alpha-tocopherol succinate inhibit hGSTO1-1 in a concentration-dependent manner with IC50 values of 2 microM and 4 microM, respectively. A Lineweaver-Burk plot demonstrated the uncompetitive nature of this inhibition. The molecular mechanism behind the inhibition of hGSTO1-1 by alpha-tocopherol esters (vitamin E) is important for understanding neurodegenerative diseases, which are also influenced by vitamin E.
Acta Biochim Pol 2006
PMID:Tocopherol esters inhibit human glutathione S-transferase omega. 1701 44

The present study was undertaken to assess the ameliorative effect of Emblica officinalis aqueous extract on ochratoxin-induced lipid peroxidation in the testis of mice. Adult male albino mice were orally administered with 50 and 100 microg of ochratoxin (Groups 4, 5) in 0.2 mL olive oil/animal/day for 45 days. The results revealed a significant increase in LPO (lipid peroxidation) in the testis of mice treated with ochratoxin compared to that of vehicle control (Group 2). The levels of non-enzymatic antioxidants: GSH (glutathione) and TAA (total ascorbic acid) as well as enzymatic antioxidants: SOD (superoxide dismutase), CAT (catalase), GPX (glutathione peroxidase), GRX (glutathione reductase) and GST (glutathione transferase) were significantly decreased in the testis of ochratoxin-treated mice. Oral administration of Emblica officinalis aqueous extract (2 mg/animal/day) along with ochratoxin (Groups 6, 7) for 45 days, caused, significant, amelioration in ochratoxin-induced LPO by increasing the contents of non-enzymatic (GSH and TAA) and activities of enzymatic (SOD, CAT, GPX, GRX and GST) antioxidants in the testis of mice as compared with those given ochratoxin alone animals (Groups 4, 5). Thus, oral administration of Emblica officinalis aqueous extract along with ochratoxin significantly ameliorates ochratoxin-induced lipid peroxidation in the testis of mice.
Acta Pol Pharm
PMID:Emblica officinalis aqueous extract ameliorates ochratoxin-induced lipid peroxidation in the testis of mice. 1866 24

Actin, the major component of the cytoplasmic skeleton, has been shown to exist in the nucleus. Nuclear actin functions in several steps of the transcription process, including chromatin remodelling and transcription initiation and elongation. However, as a part of PICs (pre-initiation complexes), the role of actin remains to be elucidated. In the present study, we identified RHA (RNA helicase A) as an actin-interacting protein in PICs. Using immunoprecipitation and immunofluorescence techniques, we have shown that RHA associates with beta-actin in the nucleus. A GST (glutathione transferase) pulldown assay using different deletion mutants revealed that the RGG (Arg-Gly-Gly) region of RHA was responsible for the interaction with beta-actin, and this dominant-negative mutant reduced the recruitment of Pol II (RNA polymerase II) into PICs. Moreover, overexpression or depletion of RHA could influence the interaction of Pol II with beta-actin and beta-actin-involved gene transcription regulation. These results suggest that RHA acts as a bridging factor linking nuclear beta-actin with Pol II.
 ...
PMID:RNA helicase A acts as a bridging factor linking nuclear beta-actin with RNA polymerase II. 1930 9

The esophageal squamous cell carcinoma is multifactorial disease involving genetic and environmental factors. The paper presents most important human data on the polymorphisms of selected genes that have been linked with higher risk of the neoplasm. The most widely studied group were genes encoded molecules engaged in biotransformations of xenobiotics, in particular potential carcinogens, like alcohol (ADH2) and aldehyde (ALDH2) dehydrogenases, various isoenzymes of cytochrome P450 (CYP1A1, CYP2E1) and glutathione S-transferase (GSTM1, GSTT1, GSTP1). High interest was also put for polymorphism in DNA repair genes, i.e., OGG1, XRCC1, XPD, XPG and MGMT as well as genes associated with nucleotide biosyntesis like methylenotetrahydrofolate reductase and thymidylate synthase and in control of cell cycle and apoptosis e.g., p53, Fas, FasL or TNF. Furthermore, it was revealed that predisposition to cancer in certain individual could be determined by coexistence of unprofitable allele of a few genes. Introduction of genetic screening test allows effective, purpose-oriented methods of prevention and in patients suffered from the cancer--application of optimal therapy and minimization of side-effects.
Pol Merkur Lekarski 2009 Feb
PMID:[Genetic base of esophageal squamous cell carcinoma susceptibility]. 1938 10

Mature, fully active human immunodeficiency virus protease (PR) is liberated from the Gag-Pol precursor via regulated autoprocessing. A chimeric protease precursor, glutathione S-transferase-transframe region (TFR)-PR-FLAG, also undergoes N-terminal autocatalytic maturation when it is expressed in Escherichia coli. Mutation of the surface residue H69 to glutamic acid, but not to several neutral or basic amino acids, impedes protease autoprocessing in bacteria and mammalian cells. Only a fraction of mature PR with an H69E mutation (PR(H69E)) folds into active enzymes, and it does so with an apparent Kd (dissociation constant) significantly higher than that of the wild-type protease, corroborating the marked retardation of the in vitro N-terminal autocatalytic processing of TFR-PR(H69E) and suggesting a folding defect in the precursor.
 ...
PMID:Modulation of human immunodeficiency virus type 1 protease autoprocessing by charge properties of surface residue 69. 1945 92


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