A SUBFAMILY 2 HOMO-DIMERIC GLUTATHIONE-S-TRANSFERASE MYRS-MYRS OF CLASS-THETA IN MOUSE-LIVER CYTOSOL

A homo-dimeric subfamily 2 glutathione (GSH) S-transferase (GST) mYrs- mYrs of the class theta was isolated from mouse liver cytosol and puri fied to homogeneity. The first 28 N-terminal amino acid sequence of th e GST was completely identical to that of rat subfamily 2 GST Yrs-Yrs of the class theta. GST mYrs-mYrs cross-reacted with anti-rat GST Yrs- anti-sera but not with anti-sera raised against rat GSTs Ya-Ya (alpha) , Yb1-Yb1 (mu), and Yp-Yp (pi) and represented more than 95% of the mo use liver cytosolic GST activity to scavenge the reactive sulfate este r 5-sulfoxymethylchrysene of the potent carcinogen 5-hydroxymethylchry sene. The mouse class theta GST had little activity toward 1-chloro-2, 4-dinitrobenzene and was unretainable on GSH and an S-hexyl-GSH affini ty columns. GST mYrs-mYrs had a much higher GSH peroxidase activity to ward fatty acid hydroperoxides than did the other classes of mouse GST s. (C) 1995 Academic Press, Inc.