Enzymes lower activation energy primarily by stabilizing the transition state and by bringing substrates together in the correct orientation. They do this through several mechanisms:
- Enzymes can position substrates to resemble their transition state, reducing the energy required to reach that state.
- They bring substrates into close proximity and in the proper orientation to react, reducing entropy and making reactions more likely.
- Enzymes form temporary bonds with substrates, creating an alternative reaction pathway with lower activation energy.
- They stabilize charged groups in the transition state, often through electrostatic interactions, which lowers the energy required for the reaction.
- Enzymes can also put strain on substrate bonds or bend them to facilitate bond-breaking, making the transition state easier to achieve.
These effects lower the energy barrier for reactions to proceed, increasing reaction rates without altering the overall energy balance or the equilibrium of the reaction.
