Cytosolic and membrane-bound forms of glutathione S-transferase are encoded by two distinct supergene families.

At present, eight distinct classes of the soluble cytoplasmic mammalian glutathione S-transferases have been identified: alpha, kappa, mu, omega, pi, sigma, theta and zeta.

This gene encodes a cytoplasmic glutathione S-transferase that belongs to the mu class.

The mu class of enzymes functions in the detoxification of electrophilic compounds, including carcinogens, therapeutic drugs, environmental toxins, and products of oxidative stress, by conjugation with glutathione.

These genetic variations can change an individual's susceptibility to carcinogens and toxins, as well as affect the toxicity and efficacy of certain drugs.