Purification and characterization of sheep lung cytosolic glutathione-s-transferase isozymes

Glutathione-s-transferases (GSTs) are the group ofmultifunctional enzymes which play a key role in the detoxification of various foreign compoundsand their metabolites. In this study, sheep lung cytosolic GST isozymes were purifiedand some propertiessuch as maximum enzyme activities respect to CDNBandDCNB, isozyme compositions, pH, temperature,DCNBandCDNB dependency ofGSTs activity aswell asmetal inhibition profilewere examined. The specific activity of lung GST towards CDNBwas determined 336 ± 73 nmol/min/mg protein versus 1.05±0.32 for DCNB. The rates of reactions were linear up to 42 µg and 4.7 mg of sheep cytosolic proteins for CDNB and DCNB, respectively. The sheep lung GSTs showed itsmaximumactivity at a broad pH range between 6.6-7.6 towards CDNB, while at pH value of around 8.0 towards DCNB. Sheep lung cytosolic GSTs showed different inhibition patterns by metal ions such as Ni2+,Cd2+, Ba2+, Mn2+, Co2+, Cu2+, Pb2+ and Zn2+. The identification of new and more potent GSTs could be useful for industrial applications.