Structural evidence for three different types of glutathione transferase in human tissues

AbstractCytosolic glutathione transferase was purified from human placenta and human liver. Three different forms of the enzyme were obtained, the acidic (π), the near-neutral (μ), and the basic (α-ϵ) forms; two had free α-amino groups (π,μ) and one had a blocked α-amino group (α-ϵ). N-terminal sequence analyses and total compositions gave clearly different results for each form, although transferases π and μ showed 35% sequence homology in the N-terminal regions, with a 1-residue shift in starting position. Consequently, the proteins are concluded to be products of three discrete but related genes