Question

Consider the conversion of succinate to fumarate in the Citric Acid Cycle (reaction below). This reaction is endergonic under standard conditions (ΔGo’≈ 6 kJ/mol). How might this reaction be made favorable under equilibrium conditions? Your answer should include the relationship of this reaction to a canonical electron transport chain (i.e. an electron transport chain that uses oxygen as a terminal electron acceptor).

Answer 1

Succinate oxidation to fumarate The following reactions transform succinate to regenerate oxalacetate. The first of these reactions is carried out by an oxidation catalyzed by succinate dehydrogenase. The hydrogen acceptor is FAD, since the free energy change is insufficient to allow NAD to interact. The final product is fumarate.

Step-by-step explanation:

The condensation reaction of GDP + Pi and the hydrolysis of Succinyl-CoA involve the H2O necessary to balance the equation.