Fig 4. Determination of the molar extinction coefficient of ThT bound to Sup35p amyloid fibrils.
(a) Concentration of ThT bound to amyloid fibrils (Cb) as a superposition of the concentrations of dye bound to mode 1 (Cb1) and mode 2 (Cb2). (b) 3D dependence of Ab = Ab1 + Ab2 = εb1Cb1l + εb2Cb2l on Cb1 and Cb2. The experimental data and the values of the molar extinction coefficients εb1 and εb2 obtained by multiple nonlinear regression are presented. (c) Absorption spectra of ThT for mode 1 and mode 2 of the binding to Sup35p amyloid fibrils in units of the molar extinction coefficient.