Anionic glutathione S-transferases in shrimp eyes

1. Two anionic isoenzymes of glutathione transferases (EC 2.5.1.18), QI and QII, have been purified from the eyes of the shrimp Penaeus japonicus by using a combination of S-hexylglutathione affinity column chromatography and Mono-Q fast protein liquid chromatography (f.p.l.c.). 2. Both QI and II glutathione S-transferases are homodimers. They show similarity in substrate specificities and pH optima, but not in isoelectric points. 3. QI is distinct from QII by anion-exchange f.p.l.c., reverse-phase h.p.l.c. chromatography and amino acid sequencing analysis. QI has N-terminal amino acid sequences homologous to mu glutathione S-transferase, whereas QII is homologous to theta glutathione S-transferases.