Figure 4

Tryptic fingerprints indicate both EC-SOD homo- and hetero-dimers. The partially separated EC-SOD dimers were subjected to trypsin cleavage and the generated peptides isolated by reverse-phase HPLC. Two peaks indicate the presence of aEC-SOD (35.5 min) or iEC-SOD (38.2 min) as indicated. Three data sets were collected: F1, solid line; F2, dashed line; F3, dotted line) and normalized using the peak representing Val24-Arg34 (*). The yield of this peptide did not differ between aEC-SOD and iEC-SOD. The level of the two folding variants could be estimated by measuring the ratio of absorbance between the peaks representing aEC-SOD and iEC-SOD and the Val24-Arg34 peptide. The obtained ratio is indicated.