Investigation of the effects of purification and characterization of turkey (Meleagris gallopavo) liver mitochondrial thioredoxin reductase enzyme and some metal ions on enzyme activity

Authors : Yusuf TEMEL, Ö İrfan KÜFREVİOĞLU, Mehmet ÇİFTCİ

Pages : 48-60

View : 24 | Download : 9

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The thioredoxin system, found in all living creatures, consists of thioredoxin protein insert ignore into journalissuearticles values(Trx);, thioredoxin reductase enzyme insert ignore into journalissuearticles values(TrxR);, and NADPH. In this study, turkey liver mitochondrial TrxR enzyme with 3.07 EU $\times $ mg$^{-1}$ specific activity was purified 990-fold in a yield of 2.05{\%} using 2`,5`-ADP Sepharose 4B affinity chromatography. The purity of the enzyme was measured and the molecular weight of its subunits was determined to be 45.5 kDa by SDS-PAGE. The molecular mass of the enzyme`s natural state was found to be 88 kDa using Sephadex-G 150 gel filtration chromatography. In addition, characteristic and kinetic properties of the enzyme were determined. Then the inhibitory effects of some heavy metal ions insert ignore into journalissuearticles values(Ag$^{+}$, Fe$^{3+}$, Cd$^{2+}$, Cu$^{2+}$, Zn$^{2+}$, Pb$^{2+}$, Ni$^{2+}$, and Co$^{2+});$ on the activity of TrxR enzyme were examined under in vitro conditions. IC$_{50}$ values were found with the heavy metal concentration with which 50{\%} of the activity of the TrxR enzyme was inhibited. Finally, K$_{i}$ values for these substances were calculated from the Lineweaver--Burk plots. It was determined that Ag$^{+}$, Fe$^{3+}$, Cd$^{2+}$, Cu$^{2+}$, and Zn$^{2+}$ ions inhibited TrxR enzyme, Pb$^{2+}$ ion increased enzyme activity, and Ni$^{2+}$ and Co$^{2+}$ ions had no effect on enzyme activity.
Keywords : Thioredoxin reductase, characterization, metal, inhibition