Glutathione transferase omega 1 catalyzes the reduction of S-(phenacyl)glutathiones to acetophenones.

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Board PG, Anders MW

Glutathione transferase omega 1 catalyzes the reduction of S-(phenacyl)glutathiones to acetophenones.

Chem Res Toxicol. 2007 Jan;20(1):149-54.

PubMed ID

17226937 [ View in PubMed

]

Abstract

S-(Phenacyl)glutathione reductase (SPG-R) plays a significant role in the biotransformation of reactive alpha-haloketones to nontoxic acetophenones. Comparison of the apparent subunit size, amino acid composition, and catalysis of the reduction of S-(phenacyl)glutathiones indicated that a previously described rat SPG-R (Kitada, M., McLenithan, J. C., and Anders, M. W. (1985) J. Biol. Chem. 260, 11749-11754) is homologous to the omega-class glutathione transferase GSTO1-1. The available data show that the SPG-R reaction is catalyzed by GSTO1-1 and not by other GSTs, including the closely related GSTO2-2 isoenzyme. In the proposed reaction mechanism, the active-site cysteine residue of GSTO1-1 reacts with the S-(phenacyl)glutathione substrate to give an acetophenone and a mixed disulfide with the active-site cysteine; a second thiol substrate (e.g., glutathione or 2-mercaptoethanol) reacts with the active-site disulfide to regenerate the catalytically active enzyme and to form a mixed disulfide. A new spectrophotometric assay was developed that allows the rapid determination of SPG-R activity and specific measurement of GSTO1-1 in the presence of other GSTs. This is the first specific reaction attributed to GSTO1-1, and these results demonstrate the catalytic diversity of GSTO1-1, which, in addition to SPG-R activity, catalyzes the reduction of dehydroascorbate and monomethylarsonate(V) and also possesses thioltransferase and GST activity.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Glutathione	Glutathione S-transferase omega-2	Protein	Humans	Unknown	Not Available	Details

Polypeptides

Name	UniProt ID
Glutathione S-transferase omega-1	P78417	Details