Glutathione S-transferase

The Glutathione S-transferase (GST) family of enzymes comprises a long list of cytosolic, mitochondrial, and microsomal proteins which are capable of multiple reactions with a multitude of substrates, both endogenous and xenobiotic.

Families of GST

• Mammalian
  • Alpha
    • A1-1
    • A2-2
    • A3-3
    • A4-4
    • hGST5.8 (putative)
  • Mu
    • M1-1
  • Pi
    • P1-1
  • Theta
  • Zeta
  • Omega

Structure of GSTs

Mammalian cytosolic GSTs are homodimeric, and the monomers are in the range of 22-29 kDa. They are active over a wide variety of substrates with considerable overlap.

GSTs and Biotransformation

Glutathione S-transferases are considered, among several others, to contribute to the phase II biotransformation of xenobiotics. Drugs, poisons, and other compounds not traditionally listed in either groups are usually somewhat modified by the phase I and/or phase II mechanisms, and finally exreted from the body. GSTs contribute to this type of metabolism by conjugating these compounds (often electrophilic and somewhat lipophilic in nature) with reduced glutathione to facilitate dissolution in the aqueous cellular and extracelluar media, and from there, out of the body.