Thiamine is a cofactor for all of the following enzymes except:
(A) Alpha ketoglutarate dehydrogenase (B) Branched-chain keto-acid dehydrogenase (C) Succinate dehydrogenase (D) Pyruvate dehydrogenase.
(C) 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.