This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Substrate level phosphorylation is catalysed by which enzyme? 
Select and explain. 
A. Succinate dehydrogenase, B. Alpha keto glutarate dehydrogenase, C. Succinate thiokinase, D. Malate dehydrogenase
C: Succinate thiokinase
Answer: C: Succinate thiokinase 
Explanation: In TCA Cycle, Fifth step: Generation of succinate. The reaction involves a substrate level phosphorylation whereby a high energy phosphate is generated from the energy trapped in the thioester bond of succinyl CoA. The enzyme is succinate thiokinase. The molecule of GDP is phosphorylated to GTP and succinate is formed.Ref: DM Vasudevan, 7th edition, page no: 248