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PFe(0) PFe+0, 3. Consider the interchange of O2 and CO coordinated to myoglobin, an iron porphyrin denoted as PFe: ; PFe +CO PFe(CO) k_1 Making the steady-state approximation for [PFe), derive the rate law. Next, repeat the derivation including the reverse step with k.(i.e. add a step to the mechanism). If [CO] and [O2] are much greater than [PFe(O2)]o, what is the expression for ke, the effective rate constant for approaching equilibrium