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)

The presence of the DNA repair protein O(6)-alkylguanine-DNA alkyltransferase (AGT) paradoxically increases the mutagenicity and cytotoxicity of 1,2-dibromoethane (DBE) in Escherichia coli. This enhancement of genotoxicity did not occur when the inactive C145A mutant of human AGT (hAGT) was used. Also, hAGT did not enhance the genotoxicity of S-(2-haloethyl)glutathiones that mimic the reactive product of the reaction of DBE with glutathione, which is catalyzed by glutathione S-transferase. These experiments support a mechanism by which hAGT activates DBE. Studies in vitro showed a direct reaction between purified recombinant hAGT and DBE resulting in a loss of AGT repair activity and a formation of an hAGT-DBE conjugate at Cys(145). A 2-hydroxyethyl adduct was found by mass spectrometry to be present in the Gly(136)-Arg(147) peptide from tryptic digests of AGT reacted with DBE. Incubation of AGT with DBE and oligodeoxyribonucleotides led to the formation of covalent AGT-oligonucleotide complexes. These results indicate that DBE reacts at the active site of AGT to generate an S-(2-bromoethyl) intermediate, which forms a highly reactive half-mustard at Cys(145). In the presence of DNA, the DNA-binding function of AGT facilitates formation of DNA adducts. In the absence of DNA, the intermediate undergoes hydrolytic decomposition to form AGT-Cys(145)-SCH(2)CH(2)OH.
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PMID:Paradoxical enhancement of the toxicity of 1,2-dibromoethane by O6-alkylguanine-DNA alkyltransferase. 1215 4

The aim of this study was to investigate the effect of SCH 58261, a selective adenosine A(2A) receptor (A(2A)R) antagonist, on kainic acid (KA)-induced seizures in 21-day-old rats. Rats were pretreated with SCH 58261 (1 or 3 mg/kg) by intraperitoneal (i.p.) route 30 min before KA (10 mg/kg, i.p.) administration. The appearance of clonic seizures, the latency for the onset of the first clonic seizure episode, and the number of deaths induced by KA were evaluated. To test the hypothesis of the oxidative imbalance induced by KA exposure, reactive species (RS) levels, catalase (CAT), glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities in the brains of rats were measured. Both doses of SCH 58261 prolonged the latency for the onset of the first clonic seizure episode. SCH 58261, at the highest dose, decreased the appearance of clonic seizures as well as the mortality rate induced by KA administration. SCH 58261, at the dose of 3 mg/kg, was also effective in protecting against alterations in oxidative stress parameters (RS levels, CAT, GPx, and GST activities) in the brains of young rats exposed to KA. Our data reveal that SCH 58261 was protective against the neurotoxicity induced by KA. Therefore, the blockade of A(2A)R might represent a novel approach for the treatment of seizures.
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PMID:Selective blockade of A(2A) receptor protects against neurotoxicity induced by kainic acid in young rats. 2163 84