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)

In order to clarify the expression of cytochrome P450 and glutathione S-transferase in human esophagus, 41 samples of human esophagus with squamous-cell carcinoma were investigated by immunoblot analysis and enzyme assays. Cytochrome P450 1A2/1 was clearly expressed in microsomes, and the amount in samples with tumorous tissue was significantly greater than that in samples without tumourous tissues or in liver; cytochrome P450 2B6 and 3A4/3 were expressed polymorphically. Aryl hydrocarbon hydroxylase activity was detected in microsomes and was greater in samples from smokers than non-smokers. Patients who both smoked and drank alcohol, however, had activity similar to that of patients without these habits. Glutathione S-transferase M1 and A1/2 protein existed polymorphically in cytosol, and glutathione S-transferase P1-1 was detected in all samples. The frequency of expression of the glutathione S-transferase A1/2 protein was greater in patients with M1 protein than in those without; no difference in the expression was seen for glutathione S-transferase P1-1. Neither smoking nor drinking influenced the expression or activity of glutathione S-transferase. Our data support the idea that some carcinogens can be directly activated or inactivated in human esophageal epithelium.
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PMID:Expression of cytochrome P450s and glutathione S-transferases in human esophagus with squamous-cell carcinomas. 870 52

Recent data suggest that plasma levels of the phase II detoxification enzyme glutathione S-transferase alpha may be a sensitive indicator of hepatocellular integrity in acute liver disorders but little information is available in chronic hepatic disorders. Using a newly developed enzyme linked immunosorbent assay, glutathione S-transferase A1-1 (GSTA1-1) levels were measured in 279 plasma samples from patients with chronic liver disorders. Results were categorized as normal or elevated plasma GSTA1-1 and normal or elevated plasma aspartate aminotransferase (AST) levels. In 24 patients with alcoholic liver cirrhosis, plasma GSTA1-1 levels were not significantly different from a group of 350 healthy controls and only one patient (4%) had an elevated GSTA1-1 level while 10 (42%) patients had elevated AST activities. In samples from patients with primary biliary cirrhosis (n = 150), primary sclerosing cholangitis (n = 26) or chronic hepatitis (n = 79) significantly (P < 0.0001) elevated plasma GSTA1-1 concentrations were detected in 25 (17%), 7 (27%) and 17 (22%) of the samples, respectively. AST activities were increased in a higher percentage of samples in all three disorders: 89%, 88%, and 57%, respectively. Plasma GSTA1-1 and AST levels were significantly correlated (P < 0.005) in the above mentioned disorders but not in alcoholic liver cirrhosis. It is concluded that plasma GSTA1-1 is not a sensitive parameter for the detection of hepatocellular damage in chronic liver disorders.
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PMID:Plasma glutathione S-transferase alpha 1-1 levels in patients with chronic liver disorders. 904 44

The binding interactions between dimeric human class alpha glutathione S-transferase A1-1 (GST A1-1) and aflatoxin B1 or sulphobromophthalein (BSP) were characterised. Aflatoxin B1 binds to GST A1-1 with a stoichiometry of 1.1 mol/mol of dimeric enzyme. The binding interaction, which can be described by a hyperbolic saturation isotherm (Kd = 8+/-2 microM), does not induce major structural changes in the enzyme, nor does it inhibit enzymatic activity. The average distance between the single tryptophan residue (Trp20) of GST A1-1 and protein-bound aflatoxin B1 was calculated to be 22.7 A by means of fluorescence resonance energy transfer. The aflatoxin-binding region, according to this calculated distance, was determined to be located in the dimer interface cleft near the crystallographic two-fold axis. Hill-plot analyses suggest that a positive co-operative interaction exists between BSP and the dimeric GST A1-1 (h = 1.6+/-0.1; K' = 14+/-0.6 microM). The binding of BSP induces a conformational change in the enzyme which is accompanied by a decrease in the molecular flexibility and in the solvent-accessible properties of the enzyme's Trp20 residue. Site-directed mutagenesis of Trp20 (Trp20-->Phe) confirms that this residue is situated in the binding environment and although it is not essential for BSP binding, it is involved in the interaction. Furthermore, the structural change associated with BSP binding alters the hyperbolic character of the glutathione saturation curve. This indicates that there may also be a cooperative interaction between glutathione and BSP or that BSP binding induces asymmetric functioning of the two enzyme subunits so that they become unequal in catalytic activity.
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PMID:Aflatoxin B1 and sulphobromophthalein binding to the dimeric human glutathione S-transferase A1-1: a fluorescence spectroscopic analysis. 982 90

A method for the sensitive determination of tetrahydrothiophene (THT) in cytosolic incubation mixtures was developed. Busulfan conjugation with glutathione was predominantly catalysed by glutathione S-transferase A1-1 (GST A1-1) and THT was released from the primary metabolite by alkalization. After liquid-liquid extraction using n-pentane separation and quantification of the product was performed by gas chromatography with a mass-selective detector. The method showed good sensitivity, accuracy and reproducibility with a detection limit of 2 ng ml(-1) and a limit of quantification of 5 ng ml(-1). The suitability of the method is shown for enzyme kinetic studies in human liver cytosol as well as for determination of GST A1-1 activity.
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PMID:Determination of tetrahydrothiophene formation as a probe of in vitro busulfan metabolism by human glutathione S-transferase A1-1: use of a highly sensitive gas chromatographic-mass spectrometric method. 1043 68

Patients with sickle cell anemia exhibit mild to moderate renal and liver damage. Glutathione S-transferase A1-1 is produced during kidney and liver damage. We hypothesized that cellular damage in sickle transgenic mice would lead to increased serum and urine murine glutathione S-transferase A1-1 levels. Levels of murine glutathione S-transferase A1-1 in the serum and urine of S+S-Antilles, NY1DD, and control mice were measured by ELISA, which revealed that the serum of S+S-Antilles mice, relative to controls, had elevated levels of murine glutathione S-transferase A1-1 (P = 0.005) as did NY1DD mice (P = 0.02, baseline vs. 2-day hypoxia). Serum liver enzymes, such as aspartate amino transferase and alanine amino transferase, as well as lactate dehydrogenase were increased in S+S-Antilles mice relative to controls (P = 0.000006, P = 0.0003, and P = 0.029, respectively). Urine murine glutathione S-transferase A1-1 of S+S-Antilles mice, as well as NY1DD mice under hypoxic stress, was not significantly different from controls. Murine glutathione S-transferase class-mu was measured by ELISA in the urine of sickle transgenic mice and control mice to define the location of tubular damage at the proximal convoluted tubule; murine Glutathione S-transferase class-mu was below the limit of detection. These findings suggest that elevated levels of murine glutathione S-transferase A1-1 in the serum reflect release during liver damage and that proximal tubular damage does not lead to appreciable urinary murine glutathione S-transferase A1-1.
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PMID:Murine glutathione S-transferase A1-1 in sickle transgenic mice. 1761 91

This study aimed to enhance the drug metabolism function of the human hepatoma cell line C3A and to explore the related significance for patients with severe liver disease. The important liver phase I and phase II drug metabolism enzymes, cytochrome P450 3A4 (CYP 3A4) and glutathione S-transferase A1 (GST A1), were constructed into a double expression vector and then transfected into C3A cells. Furthermore, in order to increase the expression of CYP 3A4 and GST A1, they were optimized according to human optimal codons. Another double-expression vector, pBudCE4.1-optimized CYP 3A4-optimized GST A1, was constructed and then transfected into C3A to establish a stable cell line. The drug metabolism function of C3A was evaluated. Sequence determination and analysis results showed that the recombinant plasmid pBudCE4.1-CYP 3A4-GST A1 met the application standard and its transfection was successful. The expression and activity of CYP 3A4 and GST A1 in unoptimized C3A cells were higher than those in blank C3A cells. Unoptimized C3A had a better drug metabolism function. Although some C3A cells transfected with pBudCE4.1-optimized CYP 3A4-optimized GST A1 survived, they grew slowly, and were therefore not applicable in clinical practice. Unoptimized C3A is superior to blank C3A in drug metabolism, and could be applied in the bioartificial liver support system as a new material.
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PMID:Establishment of cytochrome P450 3A4 and glutathione S-transferase A1-transfected human hepatoma cell line and functional analysis. 2478 12