Experimental Analysis of Metabolic Control

The following is a summary of the experimental steps that should be carried out, preferably in the sequence suggested (although this may not always be possible), when investigating control of a metabolic pathway  

Identify which steps are regulated by external regulators. 

Points 1-4 are discussed below 5 and 6 are covered in earlier sections. 

A reaction is nonequilibrium if the rate of the reverse component of the reaction is much less than the rate of the forward component, and a reaction is near-equilibrium if the rates of the forward and reverse components of the reaction are similar. In the following examples, where the numbers refer to the actual rates in either direction, the reactions Ei and E3 are considered to be nonequilibrium, whereas E2 is considered to be near-equilibrium. 

The important difference between the two types of reaction is that, with a near-equilibrium reaction, changes in the concentration of product can change the rate of the reverse reaction and hence can influence the flux through the reaction by a mass action effect. 

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