Characterization of the Major Glutathione Transferases in Carp Liver

Abstract

In fish, glutathione S-transferases are very important in the detoxification of water-borne pollutants. Carp, which often live and thrive under extreme conditions of water pollution, have been recommended by the European Community as an ideal species to test for the effect of various chemical substances often found in the aqueous environment. In this paper we describe the purification and kinetic characterization of the three major forms of glutathione S-transferase in carp liver cytosol. The main step for purification was affinity chromatography on S-hexylglutathione-Sepharose 6B and the isoenzymes have been separated by isoelectric focusing at pH 7.7, 7.3, 7.1. Values of Km and kcat/Km for both reduced glutathione and 1-chloro-2,4-dinitrobenzene as substrates have been determined, and the isoenzymes characterized with several substrates and inhibitors. J. Exp. Zool. 284:130–136, 1999. © 1999 Wiley-Liss, Inc.