ABSTRACT
Mercapturate formation as a mechanism for the physiological metabolism and excretion of xenobiotics was known in the nineteenth century.
However, it was not until 1961 that an enzymatic reaction responsible for the first step in the conjugation of xenobiotics with glutathione was recognized. Thus, Combes, Boyland, and others
reported on the conjugating activity in liver extracts. The enzymes, named glutathione transferases (GSTs), were originally classified on the basis of presumed substrate specificities (such as aryltransferase, alkyltransferase, epoxidetransferase, and so on),
until it became clear that the enzymes actually had overlapping specificities.
