Glutathione-S-transferase and in vitro metabolism of atrazine in freshwater algae

Glutathione-S-transferase (GST) activity toward atrazine and a model substrate was characterized in eight species of freshwater algae. All algal species exhibited measurable GST activity, and the involvement of these enzymes in atrazine metabolism was indicated by the glutathione-dependent formation of water soluble metabolites. Significant differences in GST activity were observed among the species tested; however, the differences were relatively small and did not appear to be correlated with relatively large differences in atrazine susceptibility among the same algal species. This report documents the presence of glutathione-S-transferase activity in freshwater algae, although the results indicate that it plays a limited role in conferring selective atrazine toxicity among different algal species.