PreLecture Question 17 Match each of the following SuccinylC

Pre-Lecture Question 17

Match each of the following:

Succinyl-CoA synthetase (succinate thiokinase) Succinate dehydrogenase Fumarase (fumarate hydratase) Malate dehydrogenase Couples the cleavage of the high-energy succinyl Co-A to the synthesis of a high-energy nucleoside triphoshpate. Catalyzes the final reaction of the citric acid cycle, regenerating oxaloacetate. Catalyzes the hydration of a double bond of fumarate to form malate. Catalyzes the stereospecific dehydrogenation of succinate to fumarate.

Solution

Ans.

Part A. Succinyl-CoA synthetase (Succinate thiokinase):

Succinyl CoA + Pi + NDP ß-----Succinate thiokinase-------> Succinate + CoA + NTP

Where, NDP = nucleoside diphosphate        ; NTP = nucleoside triphosphate

Match: 1. Couples the cleavage -------- nucleoside triphosphate.

Part B. Succinate dehydrogenase

Succinate + UQ <---- Succinate dehydrogenase ----> Fumarate + UQH2

Where, UQ= ubiquinone

Match: 4. Catalyze the stereospecific -------- to fumarate.  

Part C. Fumarase (fumarate hydratase)

Fumarate + H₂O <---- Fumarase ---->Malate

Match: 3. Catalyze the hydration -------- to form malate.    

Part D. Malate dehydrogenase

Malate + NADP⁺ <---- Malate dehydrogenase ---->Oxaloacetate + NADPH + H⁺

Match: 2. Catalyze the final reaction of CAC, regenerating OAA.