title: Biodegradation of alpha-hexachlorocyclohexane. VII. Resolution, purification, and characterization of an alpha-HCH dechlorinating enzyme from rat liver cytosol.
abstract: From rat liver cytosol, an enzyme was isolated which catalyzes the dechlorination of alpha-, gamma-, and delta-HCH. The enzyme also catalyzes the conjugation of GSH with 1,2-dichloro-4-nitrobenzene, and with 1 -chloro-2,4-dinitrobenzene. The enzyme has a molecular weight of about 46000 and its molecule is composed of two subunits of similar size. The optimum for the dechlorination of alpha-HCH lies at pH 8.0. The Michaelis constant is 0.12 mM for alpha-HCH (with 1 mM GSH as constant substrate), and maximal velocity was determined to be 0.25 moles Cl- -min -1 per mole enzyme.
mesh_terms: D000818:Animals; D003600:Cytosol / Q000201:enzymology; D005978:Glutathione; D005982:Glutathione Transferase / Q000302:isolation & purification; D001556:Hexachlorocyclohexane / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008970:Molecular Weight; D011487:Protein Conformation; D051381:Rats; D014508:Urea / Q000494:pharmacology
chemical_list: D001556:Hexachlorocyclohexane; D014508:Urea; D005982:Glutathione Transferase; D005978:Glutathione