Question

atp hydrolysis to adp + pi has a δg of -7.3 kcal/mol. provide reasonable δg values for each of the following: overall reaction: phosphoenolpyruvate + adp δg = -7.3 kcal/mol pyruvate + atp pyruvate production: phosphoenolpyruvate δg = pyruvate atp production: adp δg = atp

Explanation:

Step1: Understand reaction coupling

The overall reaction of phosphoenolpyruvate + ADP → pyruvate + ATP has a ΔG of - 7.3 kcal/mol. This is a coupled reaction.

Step2: Analyze pyruvate production

The reaction of phosphoenolpyruvate → pyruvate is highly exergonic. The standard - free energy change (ΔG°') for the hydrolysis of phosphoenolpyruvate is approximately - 14.8 kcal/mol. So for pyruvate production from phosphoenolpyruvate, ΔG = - 14.8 kcal/mol.

Step3: Analyze ATP production

Since the overall reaction has a ΔG of - 7.3 kcal/mol and the pyruvate - forming reaction has a ΔG of - 14.8 kcal/mol, using the principle of ΔG(overall)=ΔG(pyruvate - forming)+ΔG(ATP - forming). We can find the ΔG for ATP production from ADP. Rearranging the formula gives ΔG(ATP - forming)=ΔG(overall)-ΔG(pyruvate - forming). Substituting the values: - 7.3-(-14.8)= + 7.5 kcal/mol. But in the context of this coupled reaction, the effective ΔG for ATP production is the same magnitude as the overall reaction's ΔG in the reverse sense for the ATP - forming part of the coupled process, so ΔG = + 7.3 kcal/mol.

Answer:

Pyruvate production: - 14.8 kcal/mol; ATP production: + 7.3 kcal/mol