Figure 3. Impact of protease treatment on stability of PrP^Sc monitored with CDI.

Typical dissociation and unfolding of (A) Type 1 PrP^Sc(129M) and (B) Type 2 PrP^Sc(129M) followed by CDI before (blue squares) and after (red circles) PK treatment; the differences in Fapp values before and after PK treatments are in triangles (green). The curves are the best fit with sigmoidal transition model to determine the midpoint (GdnHCl_1/2 value) of the curve [4]. The differential values are fitted with the Gaussian model and the peak maximum corresponds to the mean stability of sPrP^Sc as described previously [4]. The values of apparent fractional change (Fapp) of each sample aliquot are mean ± SEM obtained from triplicate measurements.