Four glutathione transferases (EC 2.5.1.18), glutathione transferases A, B, and C and a hitherto unknown form, termed X, were purified to apparent homogeneity from rat liver cytosol. They were investigated for their abilities to inactivate two mutagenic epoxides derived from the polycyclic aromatic hydrocarbon benz(a)anthracene, the K-region epoxide benz(a)anthracene 5,6-oxide and the diol-epox...

l,3-Bis(2-chloroethyl)-l-nitrosourea (BCNU) is known to be detoxi fied by a denitrosation reaction catalyzed by glutathione-dependent en zymes in rat liver cytosol (R. E. Talcott and V. A. Levin, Drug Metab. Dispos., //: 175-176, 1983). Using a modification of their procedure, we have measured the ability of different purified rat glutathione transferase isoenzymes to denitrosate BCNU. The cata...

The Saccharomyces cerevisiae genome encodes three proteins that display similarities with human GSTOs (Omega class glutathione S-transferases) hGSTO1-1 and hGSTO2-2. The three yeast proteins have been named Gto1, Gto2 and Gto3, and their purified recombinant forms are active as thiol transferases (glutaredoxins) against HED (beta-hydroxyethyl disulphide), as dehydroascorbate reductases and as d...

Leukotriene C4 synthesis was studied in preparations from mouse mastocytoma cells. Enzymic conjugation of leukotriene A4 with glutathione was catalysed by both the cytosol and the microsomal fraction. The specific activity of the microsomal fraction (7.8 nmol/min per mg of protein) was 17 times that of the cytosol fraction. The cytosol fraction of the mastocytoma cells contained two glutathione...

HIT (histidine triad) proteins, named for a motif related to the sequence HphiHphiHphiphi (phi, a hydrophobic amino acid), are a superfamily of nucleotide hydrolases and transferases, which act on the alpha-phosphate of ribonucleotides, and contain a approximately 30 kDa domain that is typically either a homodimer of approximately 15 kDa polypeptides with two active-sites or an internally, impe...

Monochlorobimane (MCB) has been used as a glutathione (GSH) specific fluorescent probe capable of delineating GSH heterogeneity in cellular systems. Generally, low concentrations of MCB (less than 50 microM) have been used to quantitatively label GSH in rodent cell lines. Incubation of the hamster cell lines, CHO AB1 and V79, with 10 microM MCB labeled 75 and 39% of the reduced GSH pool, respec...

Aminoacyl-tRNA-protein transferases (Arg-transferases) catalyze post-translational conjugation of specific amino acids to the amino termini of acceptor proteins. A function of these enzymes in eukaryotes has been shown to involve the conjugation of destabilizing amino acids to the amino termini of short-lived proteins, these reactions being a part of the N-end rule pathway of protein degradatio...

The presence of glutathione transferases and esterase activity was investigated in Rhopalosiphum padi and the effects of the cereal hydroxamic acid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) on these detoxification enzymes was studied. Activity of glutathione S-transferases and general esterases was determined for adult aphids feeding on a natural diet lacking DIMBOA and on an artif...

Bacterial butyryl-CoA CoA-transferase activity plays a key role in butyrate formation in the human colon, but the enzyme and corresponding gene responsible for this activity have not previously been identified. A novel CoA-transferase gene is described from the colonic bacterium Roseburia sp. A2-183, with similarity to acetyl-CoA hydrolase as well as 4-hydroxybutyrate CoA-transferase sequences....

Background: The glutathione S-transferase (GST) family of metabolising enzymes plays an important role in the detoxification of mutagens and carcinogens. The expression of many of these cancer susceptibility enzymes is genetically polymorphic. An increased frequency of GST-null genotypes has been associated with several malignancies. Objective: To investigate the rate of GSTT1 and GSTM1 null ge...