Stereochemistry of the microsomal glutathione S-transferase catalyzed addition of glutathione to chlorotrifluoroethene.
The stereochemistry of S-(2-chloro-1,1,2-trifluoroethyl)glutathione formation was studied in rat liver cytosol, microsomes, N-ethylmaleimide-treated microsomes, 9000g supernatant fractions, purified rat liver microsomal glutathione S-transferase, and isolated rat hepatocytes. The absolute configuration of the chiral center generated by the addition of glutathione to chlorotrifluoroethene was determined by degradation of S-(2-chloro-1,1,2-trifluoroethyl)glutathione to chlorofluoroacetic acid, followed by derivatization to form the diastereomeric amides N-(S)-alpha-methylbenzyl-(S)-chlorofluoacetamide and N-(S)-alpha-methylbenzyl-(R)-chlorofluoroacetamide, which were separated by gas chromatography. Native and N-ethylmaleimide-treated rat liver microsomes, purified rat liver microsomal glutathione S-transferase, rat liver 9000g supernatant, and isolated rat hepatocytes catalyzed the formation of 75-81% (2S)-S-(2-chloro-1,1,2-trifluoroethyl)glutathione; rat liver cytosol catalyzed the formation of equal amounts of (2R)- and (2S)-S-(2-chloro-1,1,2-trifluoroethyl)glutathione. In rat hepatocytes, microsomal glutathione S-transferase catalyzed the formation of 83% of the total S-(2-chloro-1,1,2-trifluoroethyl)glutathione formed. These observations show that the microsomal glutathione S-transferase catalyzes the first step in the intracellular, glutathione-dependent bioactivation of the nephrotoxin chlorotrifluoroethene.
Hargus
S J
SJ
Department of Pharmacology, School of Medicine and Dentistry, University of Rochester, New York 14642.
Fitzsimmons
M E
ME
Aniya
Y
Y
Anders
M W
MW
D000818:Animals; D017402:Chlorofluorocarbons; D003600:Cytosol / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism*; D006846:Hydrocarbons, Halogenated / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats
D017402:Chlorofluorocarbons; D006846:Hydrocarbons, Halogenated; C047567:S-(2-chloro-1,1,2-trifluoroethyl)glutathione; C016304:chlorotrifluoroethylene; D005982:Glutathione Transferase; D005978:Glutathione