Figure 5. Oxidative folding of BPTI catalyzed by combinations of Prx4 with each PDIs.

(A) Schematic representation of oxidative folding pathways of BPTI. R and N indicate the reduced and native forms, respectively. 1S and 2S species are ensembles of folding intermediates with corresponding numbers of disulfide bonds. The disulfide pairings in 1S species are shown between parentheses, while the missing disulfides in 2S species are indicated with the prefix ‘des’ (des species). (B) HPLC analysis of oxidative folding of BPTI catalyzed by combinations of Prx4 with each PDIs. R, 1S, 2S, and N species of BPTI were generated by incubation with Prx4 and each PDIs in buffer (pH 7.5) containing H₂O₂ for the indicated times, and the species were separated by reverse-phase HPLC. (C) Quantitative analyses of the folding intermediates. The occupancies of R + 1S, 2S, and N species were plotted as a function of refolding time. Values are the mean ± SD of three independent experiments.