Purification and partial characterization of the glutathione S-transferases in carp liver, and their interaction with 2,4-dichlorophenoxyacetic acid and 1,4-benzoquinone

The hepatic glutathione S-transferase (GST) activity in the cytosol of the freshwater fish carp (Cyprinus carpio) was enriched by glutathione affinity chromatography. The anionic (GST A1-A3) and cationic (GST C1-C3) isoenzymes were then separated in two chromatofocusing steps. SDS electrophoresis showed GST C1 to be a heterodimer with subunits of Mr 25,000 and 28,000, and all other isoenzymes to be homodimers with subunits of Mr 25,400. They were partially characterized by different biochemical parameters. The water pollutants 2,4-dichlorophenoxyacetic acid and 1,4-benzoquinone inhibited all carp GST isoenzymes, following the same kinetic inhibition patterns as for rat liver GST. It is concluded that hepatic carp GST can play an important role in the detoxication of aquatic pollutants.