Purification and characterization of glutathione S-transferase from turkey liver and inhibition effects of some metal ions on enzyme activity.

The glutathione S-transferases (EC 2.5.1.18) were purified and characterized from turkey liver for the first time. The enzyme was purified 252.7-fold with a yield of 45%, with a specific activity of 164.31 U/mg from turkey liver. The purity of the enzyme was determined by SDS-PAGE and showed two bands nearly 26 kDa and 24 kDa on the gel. The native molecular mass of the enzyme was found to be approximately 53 kDa by Sephadex G-100 gel filtration chromatography. Optimal pH, stable pH, optimal temperature, optimum ionic strength, K(m) and V(max) values for GSH and CDNB were also determined for the enzyme as 7.3, 8.5, 50 °C, 600 mM, 0.154 mM, 0.380 mM, 1.803 EU/ml, and 2.125 EU/ml, respectively. Additionally, inhibitory effects of metal ions (Cu(2+), Hg(2+), Fe(2+), Zn(2+), Ag(+), Mg(2+), Ni(2+), and Mn(2+)) were examined the enzyme's activity in vitro by performing Lineweaver-Burk graphs and plotting activity% vs., respectively.