title: Isolation of a mouse theta glutathione S-transferase active with methylene chloride.
abstract: A glutathione S-transferase metabolizing methylene chloride has been isolated from mouse liver using a variety of chromatographic methods. N-terminal and internal amino acid sequences show that the enzyme, designated GST T1-1*, is closely related to the rat Theta-class GST 5-5. The mouse enzyme, molecular mass 25000 Da, has been isolated to homogeneity in active form with an approximate yield of 2% of the cytosolic activity towards methylene chloride. GST T1-1* has a specific activity of about 5.5 micromol/min per mg of protein whereas the rat GST 5-5 is reported to have a specific activity of about 11 micromol/min per mg of protein [Meyer, Coles, Pemble, Gilmore, Fraser and Ketterer (1991) Biochem. J. 274, 409-414], demonstrating that both the rat and mouse enzymes have similar activity with this substrate. Limited evidence was obtained for a second enzyme, with a similar molecular mass (25400 Da), which had an N-terminal sequence identical to that of rat GST 12-12. This protein, which was sequenced from a band on a gel, was extremely labile and could not be isolated to homogeneity. The partially purified enzyme was not active with methylene chloride.
authors.affiliation: Zeneca Central Toxicology Laboratory, Cheshire, U.K.
authors.forename: G W
authors.initials: GW
authors.lastname: Mainwaring
authors.forename: J
authors.initials: J
authors.lastname: Nash
authors.forename: M
authors.initials: M
authors.lastname: Davidson
authors.forename: T
authors.initials: T
authors.lastname: Green
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005982:Glutathione Transferase / Q000302:isolation & purification* / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D008752:Methylene Chloride / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D008752:Methylene Chloride; D005982:Glutathione Transferase