Question

In the context of enzyme-catalyzed reactions, why is the free energy of the enzyme-substrate complex (ES) shown to be slightly lower than that of the substrate (S)?

A. ES represents a higher energy state
B. It reflects the spontaneous nature of the overall reaction
C. The diagram is inaccurate and should be corrected
D. The enzyme contributes additional energy to the complex

Answer 1

The free energy of the enzyme-substrate complex is lower than the substrate alone because the complex formation reduces the activation energy and stabilizes the transition state, thus enhancing the rate of the catalyzed reaction.

Step-by-step explanation:

In the context of enzyme-catalyzed reactions, the free energy of the enzyme-substrate complex (ES) is shown to be slightly lower than that of the substrate (S) because the complex formation stabilizes the transition state, lowers the activation energy of the reaction, and facilitates the conversion of substrates into products. The enzyme provides a site where the substrate can be held in the correct orientation to react more easily, and by virtue of the interactions within the active site, the enzyme-substrate complex becomes a lower energy state than the substrate alone. This is crucial for the enzyme's ability to catalyze the reaction more efficiently than it would occur without the enzyme, and reflects the mechanism by which enzymes decrease the activation energy to increase the rate of reaction.