Electrophoretic and immunological analysis of human glutathione S‐transferase isozymes

Abstract

Several electrophoretically distinct glutathione S‐transferase isozymes from different tissues have been purified and characterized. The data confirm the suggestion that GST‐1, GST‐2 and GST‐3 are the products of separate genetic loci. An apparently muscle‐specific isozyme termed GST‐4 has been identified and shown to differ structurally from GST‐1, GST‐2 and GST‐3. It is likely that GST‐4 is the product of an additional gene locus. Two isozymes termed GST‐5 and GST‐6 were purified from brain. GST‐5 has a different isoelectric point, but shares many structural features with GST‐1. GST‐5 may be a brain‐specific post‐translationally modified product of the GST‐1 gene. GST‐6 is an acidic isozyme found in many tissues. The data indicate that GST‐6 is composed of two dissimilar subunits that do not cross‐react with antiserum directed against GST‐1, GST‐2 or GST‐3. These observations therefore suggest that GST‐6 may have an independent genetic origin. Show more