Figure 2
Measurement of superoxide dismutase (SOD) and peroxidase activity of PschSOD and effect of inhibitors on SOD activity. (A) Evaluation of SOD activity by pyrogallol assay with increasing protein concentrations of PschSOD. Specific activity (units/mg) of the protein was calculated in the linear range of superoxide scavenging activity and displayed in the figure inset. (B) Peroxidase activity of PschSOD measured as increase in relative 2′, 7′-dichlorfluorescein (DCF) fluorescence with increasing protein concentration (as mentioned in the figure). Comparative assessment of peroxidase activity with bovine CuZn-SOD is represented as the relative DCF fluorescence at emission maxima (λmax-522 nm) under 480 nm excitation in (C). Closed circle (●) represents the PschSOD while open circle (○) with solid line represents bovine SOD. Inhibitors tested were (D) Sodium azide (E) Potassium cyanide (F) Diethyldithiocarbamate and (G) Hydrogen peroxide. The residual SOD activity was determined taking 1 unit of SOD as 100%. Potassium cyanide and diethyldithiocarbamate acts immediately on CuZn-SOD while for sodium azide and hydrogen peroxide, PschSOD was incubated at desired concentration for 20 min at 37°C and assayed for residual activity.