Figure 3.

Probing the diffusive properties of the reaction boundary for different systems. The presentation is analogous to Fig. 2: the circles indicate the values extracted via c(s) from the Lamm PDE solutions (using standard interference optical signal increments of ɛ_A = 110,000 fringes × M⁻¹ cm⁻¹, ɛ_B = 165,000 fringes × M⁻¹ cm⁻¹, and ɛ_AB = 275,000 fringes × M⁻¹ cm⁻¹), and the solid lines are the isotherms predicted by Eqs. 7, 9, and 10 for diffusion coefficient D_A⋯B (top row), sedimentation s_A⋯B (middle row), and apparent molar mass M_A⋯B (bottom row), respectively. In red are shown the results for the standard conditions for a molecule A of 40 kDa, 3.5 S rapidly interacting with a molecule B of 60 kDa, 5.0 S to form a 100 kDa, 6.5 S complex. Blue, green, and magenta depict analogous simulations under conditions that are unphysical, but probe extreme values for species' diffusion coefficients: a 10-kDa molecule A (blue); a 35-kDa molecule B (green), and a 40-kDa complex (magenta).