Inhibition of human glutathione S-transferases by 2,4-dichlorophenoxyacetate (2,4-D) and 2,4,5-trichlorophenoxyacetate (2,4,5-T). 
The phenoxyacid herbicides, 2,4-dichlorophenoxyacetate (2,4-D) and 2,4,5-trichlorophenoxyacetate (2,4,5-T), inhibit all known isoenzymes of human liver and erythrocyte glutathione (GSH) S-transferase.  However, the maximal inhibition and the I50 values vary significantly for different isoenzymes.  GSH peroxidase II activity of GSH S-transferases is also inhibited by both these compounds.  These studies suggest that the effect of these compounds on human GSH S-transferases is significantly different from that reported for rat liver enzymes.