INHIBITION OF MAMMALIAN HEPATIC GLUTATHIONE S-TRANSFERASES BY ACETYLENIC FATTY-ACIDS

Micromolar concentrations of 2 classical inhibitors of lipoxygenase, 5,8,11 -eicosatriynoic acid (ETI) and 5,8,11,14-eicosatetraynoic acid (ETYA), were found to cause a significant inhibition of the mixture of isozymes of affinity purifed rat and human liver glutathione S-transferase (GST) with activity towards 1-chloro-2,4-dinitrobenzene (CDNB). ETI was a more potent inhibitor of both rat and human liver GST than ETYA. Analysis of kinetic data suggested noncompetitive inhibition of human liver GST by ETI towards reduced glutathione and CDNB. ETI also inhibited the hepatic GST activity towards 1,2-dichloro-4-nitrobenzene, p-nitrobenzyl chloride and 4-nitropyridine N-oxide.