Systems of Connected and Aggregated Enzyme Reactions

It is often explicitly, or implicitly, considered that an enzyme reaction occurring under steady state conditions is a system that collects connected states of the enzyme that appear during the reaction. Moreover, there is little doubt that many enzymes in vivo are aggregated as multienzyme complexes in such a way that one can wonder whether the corresponding enzyme reactions are not aggregated to form a functional structure that connects and associates the elementary reactions as to form a coherent whole.

The rate equation of the global system of becomes more complex than the individual equations of the enzymes E1 and E2 in isolation. However, one can notice that the global system is dependent upon antagonistic effects exerted by system 1. A first effect is a tendency to drift towards thermodynamic equilibrium. This tendency is exerted through the rate constants of substrate binding and release. A second effect is a tendency of the system to drift from the equilibrium and is exerted through a subtle combination of catalytic and substrate binding constants . The situation is thus of the same type, but more complex, than the one already described. A global steady state of the system its organization, is the result of these interactions.