Title: Resent Progress on Studies of Cytosolic Sulfotransferases.
Abstract: Sulfation or sulfoconjugation is well kn own as a major metabolic pathway of medical drugs, pesticides and other environmental chemicals. This reaction is catalyzed by cytosolic sulfotransferase in mammals. Several forms of sulfotransferase have been isolated from experimental animals and humans, and these are classified into 4 to 6 different groups from their substrate specificities. Despite usefuln ess of this classification, exact identification of sulfotransferase form was hampered by the overlapping substrate specificity and instability after purification. Recent progress on the cDNA cloning overcomes this situation. From the deduced amino acid sequences, sulfotransferases involved in the sulfation of lipophilic chemicals become clear to consist of two major groups, arylsulfotransferase and hydroxysteroid sulfotransferase. Arysulfotransferase may be subdivided into subgroups including phenol and estrogen sulfotransferases, while hydroxysteroid sulfotransferases share broadened substrate specificity for steroids, alcohols and bile acids within groups. In this context, properties of sulfotransferases are discussed in relation to their primary structures.