Fig 4.

 Catalysis by ERp protein of the intramolecular rearrangement of the native 2-disulfide intermediate, N*, with both 2.0 mM GSH and 0.5 mM GSSG. The reactions with no enzyme (A), with PDI (B), with ERp72 (C), and with ERp61 (D) are indicated. (E) The kinetics of the native form:total BPTI ratio. Values were determined in the same manner as in Figure 2. PDI efficiently catalyzed the conversion of N* to N. ERp61 and ERp72 barely accelerated the conversion of N* to N in comparison with reaction in the absence of enzyme. Open circles, no enzyme; closed circles, 1.5 μM PDI; open squares, 1.5 μM ERp61; closed squares, 1.5 μM ERp72. GSSG, glutathione disulfide; PDI, protein disulfide isomerase; ER, endoplasmic reticulum