Fig. 3. SodC has SOD activity. (A) The SodC SOD domain was expressed in Dictyostelium as a GFP fusion protein under the Actin 15 promoter. GFP and GFP-SOD proteins were purified by immunoprecipitation with anti-GFP antibody, and normalized by western blot analysis using anti-GFP antibody. (B) Relative superoxide levels were compared after incubation with equal amounts of purified GFP or GFP-SOD protein. The relative superoxide level from GFP was set as 1.0. GFP-SOD samples exhibited an average level of 0.3 (standard deviation of 0.06) from three independent experiments.