GSTZ1 is a member of the glutathione S transferase (GSTs) super family, encoding multifunctional enzymes important in the detoxification of electrophilic molecules, including carcinogens, mutagens, and several therapeutic drugs, by conjugation with glutathione. This enzyme also plays a significant role in the catabolism of phenylalanine and tyrosine. Several transcript variants of this gene encode multiple protein isoforms. GSTZ1 shows minimal glutathione-conjugating activity with ethacrynic acid and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole and maleylacetoacetate isomerase activity. It has low glutathione peroxidase activity with T butyl and cumene hydroperoxides and is able to catalyze the glutathione dependent oxygenation of dichloroacetic acid to glyoxylic acid. Highest expression in liver followed by kidney, skeletal muscle and brain. Also expressed in melanocytes, synovium, placenta, breast and fetal liver and heart.