Figure 4.

Inhibitor studies of recombinant VuFeSOD and SOD isozymes of cowpea. Four native gels (15% [w/v] acrylamide) were run with identical samples. Three of them were incubated, before SOD activity staining, with potassium phosphate buffer alone, buffer plus KCN, and buffer plus H₂O₂, respectively. The fourth gel (without inhibitors) was used for the immunoblot. Lane 1, BL21 cells (60 μg). Lane 2, Recombinant VuFeSOD (0.5 μg) treated with thrombin. Lane 3, Cowpea nodule extract (60 μg). Lane 4, Cowpea leaf extract (60 μg). Lane 1 shows the MnSOD and FeSOD, as well as the putative hybrid Mn/FeSOD (asterisk), of E. coli (Clare et al., 1984). Lane 4 shows the MnSOD and FeSOD as well as the cytosol (upper band) and plastid (lower band) CuZnSODs of cowpea leaves.