Isozyme specificity in the conversion of hepoxilin A3 (HxA3) into a glutathionyl hepoxilin (HxA3-C) by the Yb2 subunit of rat liver glutathione S-transferase.

1-14C-Labeled hepoxillin A3 is transformed by a purified preparation of glutathione S-transferase in the presence of glutathione into a glutathionyl conjugate in which the glutathione is covalently coupled to the carbon 11 position of hepoxilin A3. We have termed the glutathione conjugate hepoxilin A3-C in keeping with the established nomenclature for glutathione conjugates in the leukotriene series. Using [3H]glutathione as cosubstrate, the kinetics of the reaction were followed. Among various rat liver glutathione S-transferase isozymes, a homodimer of the Yb2 subunit showed the best activity, while isozymes containing the Ya and Yc subunits showed marginal activity with hepoxilin A3 as substrate.