GLUTATHIONE ANALOG SORBENTS SELECTIVELY BIND GLUTATHIONE-S-TRANSFERASE ISOENZYMES

Novel affinity sorbents for glutathione S-transferases (GSTs) were cre ated by binding glutathione (GSH) analogues to Sepharose 6B. The GSH m olecule was modified at the glycine moiety and at the group attached t o the sulphur of cysteine. When tested by affinity chromatography in a flow-through microplate format, several of these sorbents selectively bound GST isoenzymes. GammaE-C(Hx)-phiG (glutathione with a hexyl moi ety bound to cysteine and phenylglycine substituted for glycine) speci fically bound rat GST 7-7, the Pi-class isoenzyme, from liver, kidney and small intestine. GammaE-C(Bz)-betaA (benzyl bound to cysteine and beta-alanine substituted for glycine) was highly selective for rat sub units 3 and 4, which are Mu-class isoenzymes. By allowing purification of the isoenzymes under mild conditions that preserve activity, the n ovel sorbents should be useful in characterizing the biological roles of GSTs in both normal animal and cancer tissues.