TABLE 1.

Q_o site reactions and ranges of their rate constants allowed in different modeling trials

Numbering of reactions corresponds to Fig. 5. Ranges of published rate constants for bacterial complex III were taken from Ref. 32 and expanded to include mammalian values (35). In trial 1, values were constrained to the indicated ranges and k₅ = k₇ = 1650 s⁻¹. In trial 2, k₅ and k₇ were allowed to vary independently over the range indicated. Trial 3 and trial 4 allowed k₅ and k₇ to vary and also assumed that the rate constants of reaction 6 were defined by a function of the reduction state of cytochrome b₅₆₂: k₆ = (b₅₆₂^%redk₆^red + (100 − b₅₆₂^%red)k₆^ox)/100 and k₋₆ similarly. n/a, not applicable because the Riesk Fe-S center in reactions 5 and 7 was assumed to reoxidize instantly, and reaction 9 was considered to be essentially irreversible.

* See under “Experimental Procedures.”

** Value not known therefore arbitrarily constrained as indicated.