Catalysis and Inhibition in Homogeneous Systems

Because the primary catalytic loop is much faster than reactivation of the enzyme through pathway 5, the two last kinetic terms are negligible in front of the first, thus leading to 

Since reactions E/Ei and E2/E jointly govern the kinetics of the primary catalytic loop, [E, ] and [EiQ] are negligible. The forms remaining into play are thus E, ES, E2, E2Q, and E3. The following expression of the E2 concentration follows from the steady-state expression of the concentrations of the various forms of the enzyme, taking into account that 3[Q] 4 [S]  

Introduction of this expression into equation (6.245) leads to 

Taking into account the fact that a pure kinetic situation prevails, the equation above becomes 

Control by Substrate Diffusion At low concentrations of H202 and when the pure kinetic conditions are fulfilled, the diffusion-reaction equations pertaining to Q and S are written 

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