Figure 4.

PDI variants retain activity following reversible oxidization and reduction. A, DTNB was used to measure free thiols on the PDI variants after reduction with DTT (gray bars) and oxidation with GSSG (white bars). Samples are normalized to the reduced wild-type PDI. B, PDI variants were tested for enzymatic activity after reduction (gray bars) and oxidation (white bars) using the di-eosin-GSSG assay. The catalytically inactive AGHA was used as a negative control. Assays were performed in triplicate, and error bars represent 3σ.