Purification and characterization of an acid glutathione S-transferase from human lung.

An acid glutathione S-transferase (EC: 2.5.1.18) from human lung was purified and characterized. The purification procedure included two isoelectric focusing runs, Sephadex G-100 gel filtration, glutathione-affinity chromatography, and Sephadex G-75 gel filtration. With respect to the properties studied the acid lung transferase differed from human liver transferases alpha-epsilon, but it bore a close resemblance to the other human low pI transferases. Bilirubin affected the kinetics of the lung enzyme markedly differently as compared with transferase p, suggesting possible nonidentity between these enzymes. The acid lung transferase represented about 97% of the total glutathione transferase activity of the lung 100,000 g supernatant used in this work.