A subclass of mu glutathione S-transferases selectively expressed in testis and brain.

A subclass of glutathione S-transferases (GSTs), exemplified by the human hGSTM3 and rodent GSTM5 subunits, has properties that distinguish it from other Mu class GSTs. Thus, they originate from single copy genes that are in an inverted order and, apart from the coding regions, share little sequence homology relative to the others in the Mu cluster. The genes for this M3/M5 subgroup encode for proteins that are in many ways unique, including their extended lengths with key amino acid substitutions. The M3/M5 subclass is selectively expressed in testis and brain and could function differently from the other GSTs.