Two forms of glutathione S-aryltransferase were purified from rat liver. The only differences noted between the two forms were in the chromatographic and electrophoretic properties, which permitted the separation of the two species. The molecular weights of the enzyme and its subunits were estimated as about 50000 and 23000 respectively. The steady-state kinetics did no follow Michaelis-Menten ...

On the basis of available x-ray structures, A-class glutathione S-transferases (GSTs) contain at their C-termini a short alpha-helix that provides a 'lid' over the active site in the presence of the reaction products, glutathione-conjugates. However, in the ligand-free enzyme this helix is disordered and crystallographically invisible. An aromatic cluster including Phe-10, Phe-220, and the cata...

1. The basic glutathione S-transferases from rainbow-trout liver were more stable than the acidic ones. 2. The apparent pI values of these enzymes were lowered when they were eluted from a glutathione affinity column by reduced glutathione at pH 8.85. 3. The pI effect was not a function of the high pH alone, was diminished under conditions less favourable to glutathione oxidation, and did not o...

The glutathione transferases (EC 2.5.1.18) (GSTs) are a family of enzymes involved in the mechanism of cellular detoxification. They catalyze the nucleophilic attack of glutathione on the electrophilic centre of a number of toxic compounds. The cytosolic enzymes have two active sites per dimmer which behave independently of one another. The homodimeric (26 kDa per subunit) glutathione S-transfe...

Conjugation of xenobiotics with glutathione occurs commonly within the liver, and these glutathione conjugates are then preferentially excreted into bile. We have characterized this excretory process using primary cultured hepatocytes (24 h). 1-Chloro-2,4-dinitrobenzene rapidly entered the cells and formed a glutathione conjugate, S-(dinitrophenyl)glutathione, irrespective of the temperature of...

Blood samples of miners heavily exposed to coal dust were examined for changes in glutathione S-transferase (GST) activity. Decreased GST activity was found in red blood cells of subjects with early stages of coal workers' pneumoconiosis (International Labour Office classification 0/1-1/2) when compared with control miners. At further progression of coal workers' pneumoconiosis (> or = 2/1), th...