Department of Medicine, University of Arkansas for Medical Sciences, Little Rock 72205.
A full-length cDNA clone encoding the previously purified mouse glutathione S-transferase GST 5.7 [(1991), Biochem. J. 278, 793-799] has been isolated from a mouse lung cDNA library in lambda gt11. Sequencing of the clone revealed the presence of microheterogeneity in GST 5.7. Comparison of the deduced protein sequence with other glutathione S-transferases, together with previous information available on GST 5.7, indicates that the enzyme belongs to a novel subgroup within the alpha class of glutathione S-transferases. Members of the subgroup, which also include the rat GST 8-8 and perhaps chicken GST CL3, show high sequence homology with each other, but only moderate similarity to other alpha class enzymes. They share a substrate specificity profile that resembles pi-class enzymes, and are active in the conjugation of lipid peroxidation products.