Enzymes lower activation energy in chemical reactions. This means that they make it easier for a reaction to occur by reducing the amount of energy required to start the reaction. Enzymes achieve this by binding to the reactants (substrates) and bringing them together in the proper orientation for their chemical bonds to be broken and new bonds to be formed.
To understand this concept, it's important to know that chemical reactions require a certain amount of energy to overcome the energy barrier known as activation energy. Reactants need to acquire enough energy to undergo the chemical changes and reach the transition state, from which the reaction proceeds to completion. Activation energy acts as a sort of hurdle that reactants must overcome to start the reaction.
Enzymes, being biological catalysts, facilitate reactions by reducing the activation energy. They do not alter the overall energy change of a chemical reaction (also known as ΔG), but they make it easier for reactants to reach the transition state. This means that with the help of enzymes, reactions can occur more readily, at lower temperatures, and with greater efficiency.
Enzymes achieve this by providing an alternative reaction pathway with a lower activation energy. By binding to the reactants, enzymes stabilize their transition state, making it easier for the bonds to be broken and the reaction to proceed. This lowers the energy requirement for the reaction, allowing it to occur more easily and quickly.
So, in summary, enzymes lower activation energy in chemical reactions, making it easier for the reactions to occur. This is one of the main ways enzymes affect chemical reactions.