Question

For a reaction that can take place with or without catalysis by an enzyme, what is the effect of the enzyme on the standard free energy change of the reaction?

Answer 1

Enzymes do not affect the free energy of a reaction. That means that they do not increase or decrease how much products are formed and how much reactants are used up nor do they increase or decrease the free energy values of the products and reactants. They simply speed up reaction thereby reducing reaction time.