Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ATP-sulfurylase, cysteine synthase, homocysteine synthase, arylsulfatase and beta-cystathionase in Saccharomycopsis lipolytica are repressed on the addition of methionine, homocysteine or cysteine to the growth medium. The use of appropriate mutants enabled us to demonstrate that the synthesis of these enzymes is regulated by the system involving at least two low-molecular weight effectors--most likely cysteine and methionine (or their close derivatives).
Mol Gen Genet 1979 Jul 02
PMID:Regulation of s-amino acids biosynthesis in Saccharomycopsis lipolytica. 28 1

A method for selection of constitutive cysB mutation is described which takes advantage of the resistance of cysteine constitutive mutants to 1,2,4-triazole. Since cysM cysK double mutants are cysteine auxotrophs, by selecting for triazole resistance in cysM strains, mutants arising under this condition also should be constitutive for cysteine biosynthesis. Genetic analysis of mutants isolated by this technique showed that their mutational sites are located in the cysB region. Biochemical assays of cysteine enzymes, sulphite reductase and O-acetylserine sulfhydrylase of the mutants showed the derepressed level of these enzymes and the lack or slight repression by 1-cysteine.
Mol Gen Genet 1978 Oct 24
PMID:Method of isolation of cysteine constitutive mutants of the cysteine regulon in Salmonella typhimurium. 36 63

A 1,2,4-triazole resistant mutant of S. typhimurium has been isolated, in which serine transacetylase activity is seven times higher than in wild type. Partially purified serine transacetylase from a strain carrying the trz-312 mutation has kinetic properties which are virtually identical to those of the wild type enzyme and binds to O-acetylserine sulfhydrylase A to form a cysteine synthetase complex which is also indistinguishable from that found in wild type. Thus the increased activity of serine transacetylase associated with trz-312 appears to result from increased quantities of a kinetically normal, enzyme protein. Resistance to 1,2,4-triazole is probably due to the ability of trz-312 strains to synthesize O-acetyl-L-serine at a rapid enough rate to compensate for that utilized by the O-acetylserine triazolylase reaction. Genetic mapping experiments, using P1-mediated transduction, show that trz-312 is 91-99% linked to cysE, the structural gene for serine transacetylase. The results of three point crosses indicate that this mutation is located at one extreme end of the cysE locus, as would be expected for a promotor mutation.
Mol Gen Genet 1976 Oct 18
PMID:A mutation affecting expression of the gene coding for serine transacetylase in Salmonella typhimurium. 79 Jan 54

Nitric oxide (NO) has been demonstrated to play a protective role in cell injury. In this study, we have explored the effect of NO and two NO donors (sodium nitroprusside [SNP] and isosorbide dinitrate [ISDN]) on cellular glutathione (GSH) levels in a rat lung fibroblast cell line (RFL6 cells). SNP and ISDN significantly increased cellular GSH in RFL6 cells (5 x 10(-4) M SNP: 21.9 +/- 3.6 nmol/10(6) cells and 5 x 10(-3) M ISDN: 27.6 +/- 1.7 nmol/10(6) cells versus control: 13.2 +/- 0.4 nmol/10(6) cells; P < 0.05). The stimulatory effect of SNP and ISDN on GSH was first seen at 6 h and peaked at 12 to 24 h. A similar increase in GSH was observed in RFL6 cells exposed to 400 ppm NO for 7.5 h (NO: 20.5 +/- 3.4 nmol/10(6) cells versus control: 11.9 +/- 2.4; P < 0.05). SNP and ISDN also increased cellular GSH in bovine pulmonary artery smooth muscle cells (BPSMC) and bovine pulmonary artery endothelial cells (BPAEC). Buthionine sulfoximine (BSO) (0.01 mM), an inhibitor of the GSH synthetic enzyme gamma-glutamyl cysteine synthetase, blocked the increase in GSH in RFL6 cells seen with both SNP and ISDN. In BPAEC, exposure to NO donors for 24 h stimulated glutamate uptake (SNP: 441 +/- 19 pmol/10 min/10(6) cells and ISDN: 677 +/- 48 pmol/10 min/10(6) min/10(6) cells versus control: 222 +/- 9 pmol/10 min/10(6); P < 0.05). This effect paralleled the increase in GSH. In RFL6 cells, only SNP increased glutamate uptake after 24 h of incubation. In summary, NO and NO donors increase cellular GSH in RFL6 cells, BPAEC, and BPSMC. The mechanism of this effect is unclear but may involve upregulation of the normal GSH synthetic pathways. This observation may explain in part the protective effect of NO seen in some cell culture systems and may contribute to a protective effect against oxidant injury in vivo.
Am J Respir Cell Mol Biol 1995 Oct
PMID:Nitric oxide increases cellular glutathione levels in rat lung fibroblasts. 754 74

Liver homogenate glutathione (GSH) content, lipid peroxide levels and the activities of GSH metabolizing enzymes were studied in rats after 24 hours of galactosamine (GalN) treatment. Lipid peroxide levels increased whereas hepatic GSH content was decreased significantly. On the other hand, hepatic gamma-glutamyl cysteine synthetase activity was unaffected by GalN administration but gamma-glutamyl transpeptidase activity increased.
Res Commun Mol Pathol Pharmacol 1995 Feb
PMID:Hepatic gamma-glutamyl cysteine synthetase and gamma-glutamyl transpeptidase activities in galactosamine-treated rats. 774 60

We have isolated cDNA clones encoding cysteine synthase (CSase, EC 4.2.99.8), which catalyzes the terminal step in cysteine biosynthesis, by direct genetic complementation of a Cys- mutation in Escherichia coli with an expression library of Citrullus vulgaris (watermelon) cDNA. The library was constructed from 8-day-old etiolated seedlings of C. vulgaris in the lambda ZAPII vector, converted to a plasmid library by in vivo excision, and then used for transformation of cysteine auxotroph E. coli NK3, which lacks the cysK and cysM loci. The complementing cDNA containing a 560 bp 5'-untranslated region encodes a polypeptide of 325 amino acids of M(r) 34342. The translational product reacted with an antibody raised against CSase A of Spinacia oleracea. CSase and beta-pyrazolealanine synthase activities were demonstrated in vitro in extracts from E. coli cells expressing the cDNA. Genomic DNA blot analysis indicated the presence of a single copy of the gene, designated cysA, in the C. vulgaris genome. RNA blot hybridization indicated constitutive expression of cysA in cotyledons, hypocotyls and radicles of green and etiolated seedlings. These data suggested that this cDNA clone encodes CSase A the homolog of which in spinach is localized in the cytoplasm. The molecular phylogenetic tree of the amino acid sequences of CSases from plants and bacteria suggested that there are three families in the CSase superfamily; the plant CSase A family, the plant CSase B family and the bacterial CSase family. The proteins in the plant CSase A family are the most conserved relative to the ancestral CSase protein.
Mol Gen Genet 1994 Jul 08
PMID:Molecular cloning of a cysteine synthase cDNA from Citrullus vulgaris (watermelon) by genetic complementation in an Escherichia coli Cys- auxotroph. 804 62

The A-isozyme of O-acetylserine sulfhydrylase, a pyridoxal phosphate-dependent enzyme isolated from Salmonella typhimurium catalyzes the synthesis of L-cysteine from O-acetyl-L-serine and sulfide. The pyridoxal form of the enzyme has been crystallized in two different forms. One form is in the orthorhombic space group P2(1)2(1)2(1) with cell constants a = 144.4 A, b = 96.9 A and c = 54.3 A and contains two monomers each of molecular weight 34,000 per asymmetric unit. The second form is in a hexagonal space group with unit cell dimensions a = b = 115 A, and c = 348 A and contains two 68,000 dimers per asymmetric unit. Complete native enzyme data sets have been collected for both crystal forms using an R-Axis II detector. A search for suitable heavy-atom derivatives is underway. Although both crystal forms diffract X-rays to better than 2.5 A, the orthorhombic form is more suited to a detailed structural analysis due to the extended lifetime in the X-ray beam and the relative size of the unit cell.
J Mol Biol 1993 Jun 20
PMID:Crystallization and preliminary X-ray data for the A-isozyme of O-acetylserine sulfhydrylase from Salmonella typhimurium. 851 70

The steady state expression of glutathione S-transferases (GSTs) at both the protein and mRNA level is reported for the 60 tumor cell lines that are used for the National Cancer Institute Drug Screening Program. Individual GST isozymes were separated, identified, and quantified (with reverse-phase calibration curves) through a novel high performance liquid chromatographic procedure. GSTP1 was the predominant isozyme and was found at quantifiable levels in all but two of the cell lines. This isozyme ranged from 0.03% to 2.7% of the total cytosolic protein. For the mu family, 90% of the lines had GSTM2, 68% had GSTM3, but only 28% were positive for the M1 phenotype. The M1 proportion is lower than would be expected from the standard M1 null phenotype for human populations. Isozymes of the alpha family were detected only at very low levels in 35% of the lines. Significant quantitative correlations among enzyme activity, total enzyme protein, and mRNA were shown for GSTP1. However, such relationships were not apparent for the mu or alpha families. Levels of glutathione (GSH), and the transcript levels of other enzymes involved in GSH homeostasis were determined. gamma-Glutamyl cysteine synthetase (gamma-GCS) was present in all cell lines, but did not correlate with levels of intracellular GSH. Glyoxalase-I and gamma-glutamyl transpeptidase, both involved in GSH salvage, were found in 100% and 70% of the cell lines, respectively. Using a pattern-matching computer program, COMPARE, we compared and correlated the arrays of mRNA and protein levels with the pattern of chemosensitivity or chemoresistance of the 60 cell lines with 175 agents constituting a standard agent database. This database is composed of compounds to which a putative mechanism of action has been assigned. Although Pearson correlation coefficients relating the target and drug patterns were generally modest, when the patterns for the enzyme protein and mRNA levels for GST pi were correlated to drug sensitivity patterns, the list of 30 agents most closely matching (for which P < 0.05) was enriched with alkylating agents. gamma-GCS also showed an enrichment of alkylating agents in the COMPARE correlations, indicating that high levels of gamma-GCS may be an important determinant of resistance. In contrast, none of the other enzymes or GSH had patterns of expression that resulted in an obvious correlation to the sensitivity or resistance of alkylating agents.
Mol Pharmacol 1996 Jul
PMID:Glutathione-associated enzymes in the human cell lines of the National Cancer Institute Drug Screening Program. 870 Jan 7

We have previously observed that transforming growth factor beta 1 (TGF beta 1) produces a pro-oxidant effect and decreases cellular glutathione (GSH) levels of cultured bovine pulmonary artery endothelial cells (BPAEC) (White A. C., S. K. Das, and B. L. Fanburg. Am. J. Respir. Cell Mol. Biol. 6:364-368, 1992). In the present studies we demonstrate that 2 ng/ml TGF beta 1 reduces the uptake of two GSH precursor amino acids (cystine and glutamate) by 50% (cystine; control 359.35 +/- 100, TGF beta 1 187.7 +/- 26 pmol/10 min/10(6) cells, p < 0.05; glutamate; control 215.15 +/- 18, TGF beta 1 110.2 +/- 16 pmol/10 min/10(6) cells, p < 0.001). The inhibitory effect of TGF beta 1 on the uptake of GSH precursor amino acids persisted in the presence of buthionine sulfoximine (inhibits gamma-glutamyl cysteine synthetase, the rate limiting step in GSH synthesis) or acivicin (inhibits gamma-glutamyl transpeptidase). The uptake of leucine, an amino acid that does not serve as a precursor for GSH, was unaffected by TGF beta 1. In additional experiments TGF beta 1 decreased the levels of cellular and medium GSH-indicating that TGF beta 1 did not increase efflux of GSH from BPAEC. We propose from these observations that TGF beta 1 decreases cellular glutathione, at least in part, through down regulation of precursor amino acid transport and, thereby, its rate of synthesis.
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PMID:Transforming growth factor B1 decreases uptake of glutathione precursor amino acids in bovine pulmonary artery endothelial cells. 914 17

Exposure of animals to airborne particulates is associated with pulmonary injury and inflammation. In the studies described here, primary cultures of rat tracheal epithelial (RTE) cells were exposed to suspensions of residual oil fly ash (ROFA). ROFA exposure resulted in progressive cytotoxicity whereby the amount of lactate dehydrogenase (LDH) released was significantly greater at 24 h than at 6 h after exposure. In a dose-dependent manner, exposure to 5, 10, or 20 microg/cm2 of ROFA for 24 h resulted in cytotoxicity and detachment of cells from the collagen matrix, along with altered permeability of the RTE cell layer. ROFA exposure caused cellular glutathione levels to decrease, producing a condition of oxidative stress in the RTE cells. Treatment of RTE cells with buthionine sulfoxamine, an inhibitor of gamma-glutamyl cysteine synthetase, was found to augment ROFA-induced cytotoxicity. Treatment with dimethylthiourea (DMTU) inhibited ROFA-induced LDH release and permeability changes in a dose-dependent manner. Treatment with the nitric oxide synthase inhibitor NG-monomethyl-D-arginine (D-NMA) for 24 h was without effect. In rats intratracheally instilled with ROFA (500 microg/rat), intraperitoneal administration of DMTU (500 mg/kg) significantly ameliorated the degree of pulmonary neutrophilic inflammation present at 24 h. Overall, these in vitro findings suggest that ROFA-induced RTE cell injury may be mediated by hydroxyl-radical-like reactive oxygen species (i.e., species scavenged by DMTU) that are generated via non-nitric oxide pathways. The delay in induction of maximal RTE cell injury may reflect the time necessary to produce an oxidative burden by depleting antioxidant defenses such as cellular glutathione.
Am J Respir Cell Mol Biol 1997 Nov
PMID:Epithelial injury induced by exposure to residual oil fly-ash particles: role of reactive oxygen species? 937 14


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