GST conjugates reduced glutathione to a variety of targets including S-crystallin from squid, the eukaryotic elongation factor 1-gamma, the HSP26 family of stress-related proteins and auxin-regulated proteins in plants.

The catalytically important residues are proposed to reside in the N-terminal domain.

In plants, GSTs are encoded by a large gene family (48 GST genes in Arabidopsis) and can be divided into the phi, tau, theta, zeta, and lambda classes.

[1][2][3][4] Bacterial GSTs of known function often have a specific, growth-supporting role in biodegradative metabolism: epoxide ring opening and tetrachlorohydroquinone reductive dehalogenation are two examples of the reactions catalysed by these bacterial GSTs.

[5][6] GST seems to be absent from Archaea in which gamma-glutamylcysteine substitute to glutathione as major thiol.