Quality Control: Serially diluted SOD solutions with concentrations ranging from 0.625 to 40 units/ml are measured with the ScienCell™SOD Assay after different time of reaction, and the resulting standard curves are shown in Figure 1. % Inhibition of reduction reaction can be calculated based on the corresponding Δ A438nm/minfor each SOD concentration. Positive linear relationship between % Inhibition & logarithm of SOD concentration to the base 10 (Log [SOD concentration]) can be observed within the range of 0.625 to 10 units/ml (Figure 2).