Comparison of purified lens glutathione S-transferase isozymes from rabbit with other species

Abstract

Two glutathione S-transferase (GST) isozymes, GST-rl1 and GST-rl2, were purified from rabbit lenses and their properties were compared with those of other animals. GST-rl1 and GST-rl2 are dimeric enzymes whose subunit sizes are 24,000 and 21,500, respectively. The substrate specificities and inhibitor sensitivities of GST-rl1 and GST-rl2 are different from each other and from those of the isozymes from other animals. GST-rl1 immunologically crossreacted with the antibody against class μ GST (rat GST Yb1-Yb1), and GST-rl2 crossreacted with the antibody against class π GST (rat GST Yp-Yp). N-Terminal amino acid sequences of GST-rl1 and GST-rl2 have great homology with other class μ and class π enzymes, and thus indicate that they belong to class μ and class π, respectively. Class π GST-rl2 is inactivated by 1,2-naphthoquinone, an oxidized metabolite of naphthalene, but class μ GST-rl1 is insensitive to it. These results are similar to those of class π pig lens GST and class μ bovine lens GST. Thus, the expression pattern of GST isozymes in lens varies with animal species, and may relate to their variation in sensitivity to oxidative stress.