Figure 6.

Analysis of insulin disulfide reductase activity of GbNRX1. A, SDS-PAGE analysis of purified proteins. GbNRX1, D1 (domain 1), D2 (domain 2), D3 (domain 3), and AtTRX-h5 were expressed in E. coli, and the purified proteins were subjected to SDS-PAGE. Molecular masses (in kDa) are given on the left. B, Insulin reduction assay. Purified GbNRX1 (5, 2.5, and 1 µM) and AtTRX-h5 (5 µM) were used for the insulin reduction assay, and enzyme activity was quantified based on A₆₅₀. C, Time course of insulin disulfide reductase activity. Five micromolars of intact GbNRX1, D1 (domain 1), D2 (domain 2), and D3 (domain 3) was used and reaction buffer was used as a negative control.