Question

How does an enzyme lower the activation energy?

Answer 1

An enzyme can act in several ways to lower `E_a`. It does this by forming an enzyme-substrate (ES) complex.

1. The enzyme may hold the substrates in such a way as to distort the substrate bonds closer to their form in the transition state. This reduces the amount of energy needed to complete the transition.

2. The enzyme may create a charge distribution opposite to that of the transition state. This lowers the energy of the transition state and decreases the activation energy.

3. The enzyme may reduce the reaction entropy `ΔS^‡` by bringing substrates together in the correct orientation to react.

4. The enzyme may provide a completely different chemical pathway for the reaction. It may form new bonds in the ES complex that would be difficult to form without the enzyme.