This type of enzymes, which are found in bacteria, halobacteria, fungi, and plants, catalyse the glutathione-dependent reduction of glutathionyl-hydroquinones. The enzyme from the bacterium Sphingobium chlorophenolicum can act on halogenated substrates such as 2,6-dichloro-3-(glutathione-S-yl)-hydroquinone and 2,3,5-trichloro-6-(glutathione-S-yl)-hydroquinone. Substrates for these enzymes are often formed spontaneously by interaction of benzoquinones with glutathione.
