the effect of cadmium sulfate on the thermal stability and kinetics of peroxidase at different temperatures

in this study, the interaction of various concentrations of cadmium sulfate with peroxidase (e.c 1.11.1.7) was investigated in different temperatures (25-35 °c). for this purpose thermostability, spectrophotometry, spectroflorimetry and kinetics studies were done to obtain thermodynamic parameters including ∆g°, ∆h°m, ∆s°m, tm and also kinetics parameters including vmax and km. the results showed that cadmium sulfate caused uncompetitive inhibition at different temperatures and increasing of temperature intensified this inhibition effect. also cadmium sulfate was reduced the stability of peroxidase and reduced its tm. in the spectrophotometric studies the effect of cadmium sulfate on the peroxidase in such a way that the absorption in 275nm increased and temperatures increased it too, also the absorption in 404nm (soret bond) decreased and temperature decreased it too. totally, cadmium sulfate ions in a time- and dose- dependent manner and affected by temperature bind to the peroxidase in the heme environment and decrease the thermostability of it, and exert uncompetitive inhibition.