FIGURE 7.

Reduction of nDsbD_ox by DTT is a slow process. A series of one-dimensional ¹H NMR spectra was collected following the addition of 3 mm DTT to 0.3 mm nDsbD_ox. The first spectrum was collected ∼5 min after the addition of DTT, and subsequent spectra were collected at intervals of 5 min for 16 h. The kinetics of reduction of nDsbD_ox by DTT can be followed by monitoring the intensity of the peak at −0.36 ppm, which corresponds to the methyl group of Ala¹⁷ in reduced nDsbD (inset). The intensity of this peak, which increases with time as nDsbD is reduced, shows pseudo-first-order kinetics with a rate constant of 0.34/h. nDsbD is only 50% reduced after ∼2 h, and full reduction takes ∼12 h.