A synthesis step requires ΔG∘=+22.5kJmol−1 and must be driven by a reaction that does not involve phosphate transfer. Which of the following reactions is most appropriate to couple directly to this step?
a) Hydrolysis of GTP to GDP + Pi ; ΔG∘=−30.5kJ mol−1
b) Hydrolysis of acetyl-CoA to acetate + CoA ; ΔG∘=−31kJ mol−1
c) Hydrolysis of succinyl-CoA to succinate + CoA ; ΔG∘=−15kJ mol−1
d) Hydrolysis of creatine phosphate to creatine + Pi ; ΔG∘=−43.0kJ mol−1