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

Molecular modeling techniques have been used to derive a substrate model for class mu rat glutathione S-transferase 4-4 (GST 4-4). Information on regio- and stereoselective product formation of 20 substrates covering three chemically and structurally different classes was used to construct a substrate model containing three interaction sites responsible for Lewis acid--Lewis base interactions (IS1, IS2, and IS3), as well as a region responsible for aromatic interactions (IS4). Experimental data suggest that the first protein interaction site (pIS1, interacting with IS1) corresponds with Tyr115, while the other protein interaction sites (pIS2 and pIS3) probably correspond with other Lewis acidic amino acids. All substrates exhibited positive molecular electrostatic potentials (MEPs) near the site of conjugation with glutathione (GSH), as well as negative MEP values near the position of groups with Lewis base properties (IS1, IS2, or IS3), which interact with pIS1, pIS2, or pIS3, respectively. Obviously, complementarity between the MEPs of substrates and protein in specific regions is important. The substrate specificity and stereoselectivity of GST 4-4 are most likely determined by pIS1 and the distance between the site of GSH attack and Lewis base atoms in the substrates which interact with either pIS2, pIS3, or a combination of these sites. Interaction between aromatic regions in the substrate with aromatic amino acids in the protein further stabilizes the substrate in the active site. The predictive value of the model has been evaluated by rationalizing the conjugation to GSH of 11 substrates of GST 4-4 (representing 3 classes of compounds) which were not used to construct the model. All known metabolites of these substrates are explained with the model. As the computer-aided predictions appear to correlate well with experimental results, the presented substrate model may be useful to identify new potential GST 4-4 substrates.
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PMID:A predictive substrate model for rat glutathione S-transferase 4-4. 754 47

This study examined the advantages of the use of biomarkers as an early warning system by applying it to different shrimp farming systems in Soctrang and Camau provinces, main shrimp producers in Mekong River Delta, Vietnam. Shrimp were collected at 15 different farms divided into four different farming systems: three farms were converted from originally rice paddies into intensive shrimp farming systems (IS1, IS2, IS3); three farms were rice-shrimp integrated farming systems (RS4, RS5, RS6); three farms were intensive farming systems (IS7, IS8, IS9); six farms were extensive shrimp farming systems (From ES1 to ES6). Lipid peroxidation (LPO) and total glutathione (GSH) were measured as well as catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST) and acetylcholinesterase activities (ACHE). Organ specificity was observed between gills and hepatopancreas with generally higher activity of GST in gills (GSTG) whereas the contrary was observed for LPO level in gills (LPOG). Hierarchical clustering and principal component analysis clearly indicated that shrimp reared in extensive culture system formed a distinct group from those reared in intensive or rice-shrimp integrated systems. CAT in gills (CATG), GPX in gills (GPXG) and hepatopancreas (GPXHP) and ACHE in muscle (ACHEM) of shrimp collected in extensive farms showed a general higher level than those in intensively farmed shrimp. On the contrary, we observed clear high levels of GSTG and GST in hepatopancreas (GSTHP) and LPOG and hepatopancreas (LPOHP) of shrimp sampled in intensive and rice-shrimp integrated systems. Thus, we propose that LPO and CAT, GPX, GST and ACHE can be used as a set of biomarkers for the assessment of health condition and can discriminate between shrimp cultivated in different farming systems. These findings provide the usefulness of integrating a set of biomarkers to define the health status of shrimp in different shrimp culture systems.
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PMID:A multi-biomarker approach to assess the impact of farming systems on black tiger shrimp (Penaeus monodon). 2094 54