The relative magnitudes of FCCs would depend on the structure of the system and length of the pathway. FCCs should only be compared with each other in the same pathway but not with FCCs of other pathways.
Sensitivities can also be defined for the effect of system parameters on intracellular metabolite concentrations. The concentration control coefficients (CCC) specify the relative change in the level of the j'th intermediate Xj when the activity of the ith enzyme is changed:
where Cj denotes the concentration of Xj. Because the level of any intermediate Xj remains unchanged when all enzyme activities are changed by the same factor, the sum of all CCCs for each of the K metabolites is equal to zero :
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