What can the binding energy (ΔG_B) of an enzyme catalyzed reaction tell us?

• A. The change in the rate/speed of the reaction.
• B. The change in the equilibrium constant (K_eq) of the reaction.
• C. The change in the reaction E_A between the catalyzed & uncatalyzed transition states.
• D. a & c.
• E. All options are true.

Answer: (D)

Verified step by step guidance

1. Understand that binding energy (ΔG_B) refers to the energy released when an enzyme binds to its substrate, stabilizing the transition state and lowering the activation energy (E_A).
2. Recognize that a decrease in activation energy (E_A) due to enzyme binding increases the rate of the reaction, as per the Arrhenius equation, which relates reaction rate to activation energy.
3. Note that the equilibrium constant (K_eq) of a reaction is determined by the difference in free energy between reactants and products, not by the activation energy or binding energy. Therefore, ΔG_B does not directly affect K_eq.
4. Identify that the binding energy (ΔG_B) affects the transition state by lowering the activation energy (E_A) for the catalyzed reaction compared to the uncatalyzed reaction, thus facilitating the reaction.
5. Conclude that the binding energy (ΔG_B) is related to both the change in reaction rate (option a) and the change in activation energy between catalyzed and uncatalyzed states (option c), but not directly to the equilibrium constant (K_eq).