Which of the following would decrease activity of the citric acid cycle overall?
(I) high concentration of NADH
(II) high concentration of Ca²⁺
(III) high concentration of ATP
(IV) high concentration of citrate

Question

Quizplus · Accepted Answer

(I) High concentration of NADH inhibits the citric acid cycle by inhibiting the activity of isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, which are two key enzymes of the cycle. (III) High concentration of ATP also inhibits the cycle by inhibiting the activity of isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. (IV) High concentration of citrate inhibits the activity of citrate synthase, which is the first enzyme of the cycle. (II) High concentration of Ca²⁺ is not a relevant factor for the citric acid cycle.

Which of the Following Would Decrease Activity of the Citric