FIGURE 2.

(Top) The elementary kinetic schemes for heme-substrate relaxation and ligand migration in the absence of ligand escape. Only kinetically distinguishable states are shown. (State A) Ligand bound to the heme, substrate in position 1. (State B*) Ligand in primary docking site, substrate still in position 1. (State B°) Ligand in primary docking site, substrate relaxed to position 2. (States {C}) Collection of secondary docking sites. (Bottom) The two-line rate spectrum obtained by analytically solving either system. The band envelopes show a possible spectrum when the system is distributed because of protein statistical conformational substates.