We measured the depolymerization rate of SH3 WT fibrils in a Prometheus Panta instrument using Prometheus NT.48 Series nanoDSF high sensitivity grade capillaries. We recorded the fluorescence emission intensity at 330 and 350 nm upon excitation at 280 nm. We performed an isothermal depolymerization experiment for WT fibrils and WT monomer at 16 linearly spaced urea concentrations, from 0 to 6.4 M urea, for 10 hours at 30 µM total protein. Depolymerization buffers were prepared as described above. We ensured consistent fibril concentrations and homogeneous fibril lengths by extending the sonication step to 30 s. We calculate the fraction of soluble monomer from the fluorescence ratio, assuming fully fibrillar samples at t = 0 with 0 M urea and no fibrils present for monomer samples at respective urea concentrations. We calculated monomer release by linear regression of the first 15 to 400 minutes, depending on urea concentration.