This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Thiamine is a cofactor for all of the following enzymes except: 
Select and explain. 
A. Alpha ketoglutarate dehydrogenase, B. Branched-chain keto-acid dehydrogenase, C. Succinate dehydrogenase, D. Pyruvate dehydrogenase.
C: Succinate dehydrogenase
Answer: C: Succinate dehydrogenase 
Explanation: Ans: C. Succinate dehydrogenaseThiamin as coenzyme:Catalyzes oxidative decarboxylation reactions.3 multi-enzyme complexes catalyzing oxidative decarboxylation reactions:Branched-chain ketoacid dehydrogenase - Involved in metabolism of leucine, isoleucine & valineAlpha-ketoglutarate dehydrogenase - In citric acid cyclePyruvate dehydrogenase - In carbohydrate metabolismTransketolase reaction - In pentose phosphate pathway.Succinate dehydrogenase:Involved in redox reaction catalyzed by FMN & FAD.