Panel A: mixtures containing 50 µM scrambled RNase in 50 mM phosphate buffer, pH 7.5 containing 3 mM GSH and 0.3 mM GSSG, were incubated at 25 °C with 1 µM PDI (black circles), without (grey), with 2 µM Mia40 (red), 10 µM Mia40 (blue), 2 µM Mia40APA(purple) or 10 µM Mia40APA (green circles). Aliquots were withdrawn and measured for RNase activity (see Methods). The average activity of 3 independent reactions is plotted in Panel A and the values recorded after 2 h are summarized in Panel B.