Fig. 8.

S/R suite after optimizing the model (nine free parameters) with a dynamic Ca²⁺ buffer while holding τ_E* = 2 s. With the dynamic Ca²⁺ buffer, the model has sufficient flexibility to maintain a good fit to the DA Ref data (A) even when the rate-limiting recovery stage in the “front-end” reactions is held to a 2-s time constant (E). With these parameters, the step responses begin to show a “nose” at step onset, but still do not have the multiphasic response profile at step offset (D). The model LA flash sensitivity (F) has a slightly extended I-range (∼0.4 log units, out to a cutoff I_b of ∼ 531 R^* s^-1) in comparison to the Nikonov et al. model with τ_E* fixed at 2 s (compare with Fig. 4F). The coding for all the curves in F is as in Fig. 2F.