Fig. 8. The dependence of cytochrome c diffusibility and Bak conformation change on [tBid]. (A,C) The rate constants a and c at varying [tBid] were evaluated in a single mitochondrial preparation by the two-step procedure used in Fig. 6, but with 1 µM Ca²⁺ buffer (5 mM EGTA/4 mM Ca²⁺). (B) The basal values of the cytochrome c diffusibility constant a were determined in five mitochondrial preparations by extrapolation of lines (as in A) to zero [tBid]; mean ± s.e.m.