In a metabolic pathway, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, a substance that resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the amount of succinate molecules to those of malonic acid reduces the inhibitory effect of malonic acid. Which of the following statements correctly describes the role played by molecules described in the reaction?
A) Succinate dehydrogenase is the enzyme, and fumarate is the substrate in the reaction.
B) Succinate dehydrogenase is the enzyme, and malonic acid is the substrate in the reaction.
C) Succinate is the substrate, and fumarate is the product in the reaction.
D) Fumarate is the product, and malonic acid is a noncompetitive inhibitor in the reaction.

Question

Quizplus · Accepted Answer

Succinate is the substrate that succinate dehydrogenase acts upon to convert it into fumarate, which is the product. Malonic acid is a competitive inhibitor, not a noncompetitive inhibitor, as it competes with succinate for the active site of the enzyme.

In a Metabolic Pathway, Succinate Dehydrogenase Catalyzes the Conversion of Succinate