Absorbance difference traces at 360 nm (A, B) and 420 nm (C, D) upon addition of Cys as a function of time for the wild-type and D146K/H389T variant proteins.

<p>Panels (A, C) 0–125 ms, panels (B, D) same wavelength up to 500 ms. Note that these traces show the differences in absorbance after mixing. The absorbance at time = 0 was set to zero independently of the actual value, which means that the absolute absorbance values at different wavelengths can not be directly compared. Time constants, determed from fits with a sum of exponential functions, are also given.