Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.2.3 (glutathione synthetase)
 678 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure for synthesis of glutathione selectivity labeled with isotopes is described. A strain of Escherichia coli enriched in its content of gamma-glutamylcysteine synthetase and glutathione synthetase by recombinant DNA techniques is immobilized in a carrageenan matrix and treated with toluene to render the cells more permeable to the substrates. The immobilized cell matrix is incubated with a mixture containing the appropriately labeled amino acid, the other amino acid constituents of glutathione, ATP, and acetylphosphate. The radiolabeled product is isolated by column chromatography.
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PMID:Glutathione specifically labeled with isotopes. 286 14

The enzymatic production of glutathione (GSH) has been studied in a bioreactor system using toluene-treated cells of Escherichia coli B transformed with recombinant plasmids for gamma-glutamylcysteine synthetase (GSH-I) and glutathione synthetase (GSH-II). As reported previously the genes for both enzymes were separately cloned onto vector plasmid pBR322. The plasmid for GSH-I was designated pGS100-2 and that for GSH-II as pGS200. The effect on GSH production in the bioreactor system, containing an ATP regenerating system, of using cells containing various hybrid plasmids has now been explored. Three kinds of hybrid plasmids, designated pGS300, pGS400, and pGS500, were constructed by subcloning the genes in pGS100-2 and pGS200 onto vector plasmid pBR325. pGS300 contained the E. coli B chromosomal DNA fragment with a gene for GSH-I in the PstI site of pBR325. pGS400 also contained E. coli B chromosomal DNA fragment with a gene for GSH-II in the HindIII site of pBR325. In contrast, pGS500 contained two kinds of DNA fragments with the genes for GSH-I and GSH-II in the PstI and HindIII sites of pBR325, respectively. All the hybrid plasmids thus prepared were stably maintained in E. coli cells when chloramphenicol was included at 10 micrograms/ml in the medium. The activity of the cells containing pGS300 was higher than that of the cells containing pGS400, although the former activity did not come up to that of cells having both pGS300 and pGS400. The highest glutathione-producing activity was found in the case of the cells transformed with pGS500 carrying both genes for GSH-I and GSH-II on the vector plasmid pBR325. About 5 mg/ml of glutathione was produced by E. coli cells with pGS500 from 80 mM L-glutamate, 20 mM L-cysteine, and 20 mM glycine within 3 h at 37 degrees C.
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PMID:Construction of glutathione-producing strains of Escherichia coli B by recombinant DNA techniques. 614 39

A recombinant strain E. coli II-1, which exhibited high glutathione (GSH) biosynthetic activity and high stability, was constructed by transforming plasmid pGH501 which contains gene gsh I and gsh II into a wild type strain E. coli II. 4 g/L GSH accumulated extracellularly by using toluene-treated cell. In GSH biosynthetic system, GSH production was improved by increasing the concentration of L-glutamate, while inhibited by L-cysteine if it's concentration was beyond 20 mmol/L. In GSH biosynthetic reaction, the apparent little consumption of L-glutamate and glycine was concluded experimentally to be that toluene-treated E. coli II-1 cells still contained high concentration of L-glutamate and glycine. According to the change of energy cofactor in the GSH biosynthetic process, a possible GSH biosynthetic mechanism controlled by E. coli II-1, was proposed: the energy donator of reaction catalyzed by glutathione synthetase (GSH-II) was ADP but not ATP, the reaction was rate-limited step within the whole GSH biosynthetic process, high concentration of ADP might inhibit the activity of GSH-II. Further degradation of GSH was prevented by the addition of 100 mmol/L L-serine and potassium borate mixture. In such case, 23.0 mmol/L (about 7.1 g/L) GSH accumulated at 3 h.
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PMID:[Construction of recombinant E. coli with high glutathione biosynthetic activity and the biosynthetic process]. 1254 83

In order to gain insight into the effects of aging on susceptibility to environmental toxins, we characterized the expression of xenobiotic metabolizing enzymes (XMEs) from the livers of male F344 and Brown Norway (BN) rats across the adult lifespan. Using full-genome Affymetrix arrays, principal component analysis showed a clear age-dependent separation between young and old animals in both rat strains. Out of 1135 or 1435 genes altered between the old and young groups in the F344 or BN rats, 7 or 3% were XMEs and included members of the phase I, II, and III classes of genes. There was a 20 or 32% overlap in the gene expression profile between the two strains for F344 or BN, respectively. Lipid, ergosterol, alcohol, and fatty acid metabolism genes were also altered with age in both strains. Some of the genes altered by age exhibited a gender-dependent expression pattern in young adult rats, suggesting an increasingly feminized pattern of gene expression with age in male rats. To examine transcriptional responses across lifespan after challenge with a xenobiotic compound, BN rats were exposed to toluene by oral gavage. Toluene exposure decreased the expression of glutathione synthetase, and dramatically increased the number of phase III genes being downregulated. The expression of CYP2B2 and glutathione-S-transferase decreased with age but increased in all age groups after toluene exposure. Decreased ability to detoxify and transport chemicals out of the body with age could result in increased susceptibility to some classes of chemicals in the aging population.
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PMID:Coordinated changes in xenobiotic metabolizing enzyme gene expression in aging male rats. 1865 62