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.

Purification of glutathione S-transferase from Van Lake fish (Chalcalburnus tarichii Pallas) muscle and investigation of some metal ions effect on enzyme activity.

Glutathione S-transferases (GSTs) are an important enzyme family which play a critical role in detoxification system. In our study, GST was purified from muscle tissue of Chalcalburnus tarichii Pallas with 301.5-fold purification and 19.07% recovery by glutathione agarose affinity chromatography. The purity of enzyme was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showing a two band, because of having heterodimer structure. KM values were 1.59 and 0.53 mM for 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione (GSH), respectively. Vmax values for CDNB and GSH were also determined as 5.58 and 1.88 EU/mL, respectively. In addition, inhibition effects of Ag(+), Cu(2+), Cd(2+), Fe(3+), Pb(2+), Cr(2+), Co(2+) and Zn(2+) metal ions were investigated on the enzyme activity and IC50, Ki values were calculated for these metal ions.