Some metals inhibit the glutathione S-transferase from Van Lake fish gills.

Glutathione S-transferases (GSTs) are the superfamily of multifunctional detoxification isoenzymes and play important role cellular signaling. The present article focuses on the role of Cd2+ , Cu2+ , Zn2+ , and Ag+ in vitro inhibition of GST. For this purpose, GST was purified from Van Lake fish (Chalcalburnus tarichii Pallas) gills with 110.664 EU mg-1 specific activity and 79.6% yield using GSH-agarose affinity chromatographic method. The metal ions were tested at various concentrations on in vitro GST activity. IC50 values were found for Cd+2 , Cu+2 , Zn+2 , Ag+ as 450.32, 320.25, 1510.13, and 16.43 μM, respectively. Ki constants were calculated as 197.05 ± 105.23, 333.10 ± 152.76, 1670.21 ± 665.43, and 0.433 ± 0.251 μM, respectively. Ag+ showed better inhibitory effect compared with the other metal ions. The inhibition mechanisms of Cd2+ and Cu2+ were non-competitive, whereas Zn2+ and Ag+ were competitive. Co2+ , Cr2+ , Pb2+ , and Fe3+ had no inhibitory activity on GST.