Glutathione S-transferase Mu 2, also known as GST class-mu 2, GSTM2-2 and GSTM2, is a cytoplasm protein which belongs to the GST superfamily and Mu family. GSTM2 / GST4 contains one GST C-terminal domain and one GST N-terminal domain. The glutathione S-transferases (GSTs) are a multigene family of enzymes largely involved in the detoxification of chemicals. Eight distinct classes of the soluble cytoplasmic mammalian glutathione S-transferases have been identified: alpha, kappa, mu, omega, pi, sigma, theta and zeta. Butyrate, an important luminal component produced from fermentation of dietary fibers, is an efficient inducer of GSTs and especially of GSTM2. Butyrate may act chemoprotectively by increasing detoxification capabilities in the colon mucosa.