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

Abstract

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 164.31U/mg from turkey liver. The purity of the enzyme was determined by SDS-PAGE and showed two bands nearly 26kDa and 24kDa on the gel. The native molecular mass of the enzyme was found to be approximately 53kDa by Sephadex G-100 gel filtration chromatography. Optimal pH, stable pH, optimal temperature, optimum ionic strength, Km and Vmax values for GSH and CDNB were also determined for the enzyme as 7.3, 8.5, 50°C, 600mM, 0.154mM, 0.380mM, 1.803EU/ml, and 2.125EU/ml, respectively. Additionally, inhibitory effects of metal ions (Cu2+, Hg2+, Fe2+, Zn2+, Ag+, Mg2+, Ni2+, and Mn2+) were examined the enzyme's activity in vitro by performing Lineweaver–Burk graphs and plotting activity% vs., respectively.