Chapter 18, Problem 14P

Energetic of Fructose-1 ,6-bis P Hydrolysis (Integrates with Chapter 3.)

The standard free energy change ( $\Delta Gº\text{'}$) for hydrolysis of fructose-1.

6-bisphosphate (FBP) to fructose-S-phosphate (F-6-P) and P: is

-16.7 KJ/mol:

FBP + H₂O $\to$fructose-6-P + P_i

The standard free energy change ( $\Delta Gº\text{'}$) for ATP hydrolysis is

-30.5 KJ/mol:

ATP + H₂O $\to$ADP + P_j

1. What is the standard free energy change for the phosphofructokinase reaction:

ATP + fructose-6-P $\to$ADP + FBP

b. What is the equilibrium constant for this reaction?

c. Assuming the intracellular concentrations of [ATP] and (ADP] are maintained constant at 4 mM and 1.6 mM, respectively, in a rat liver cell, what will be the ratio of [FBP]/[fructose-6-P] when the phosphofructokinase reaction reaches equilibrium?