Still feel confusing here. Do you mean I dissociate the reaction into the following two reactions?
PyrI <-> PyrM
HM <-> HI
The reaction mechanism of the origianl reaction is Rapid Equilibrium Random Bi Bi, so the rate equation is a function of PyrI, PyrM, HM, HI and E. After the dissociation, how to use the rate equation then?
What kind of rule should I apply for the two reaction?