Rat brain glutathione S-transferases (GSTs) were studied and compared with rat hepatic GSTs in order to elucidate the mechanisms of detoxication of xenobiotics in the brain. In rat brain, the diethylaminoethyl (DEAE)-cellulose-bound fraction contained more glutathione S-transferase (GST) activity than the DEAE-cellulose-unbound fraction under conditions of 10mM Tris-HCl, pH 8.0. The group of GSTs in the DEAE-cellulose-bound fraction was found to be resolved into at least three peaks. The GST in the main peak was partially purified by Sephadex G-75 and CM-52 column chromatography. The activity was eluted as a single peak on Sephadex G-75 gel filtration, and did not bind to a CM-52 column (10mM potassium phosphate, pH 6.7). The molecular weight of the GST in the main peak was about 44000 daltons, and the enzyme consisted of YnYn (Yn subunit : M, 24500) subunits as determined by SDS/polyacrylamide gel electrophoresis. The GST activities of this main peak were inhibited by antiserum raised against peak II (YbYb subunits : Yb subunit, M, 25000) in the DEAE-cellulose-bound fraction of rat liver.
