This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
[{'content': 'Proper functioning of Kreb cycle does not occur with deficiency of \nSelect and explain. \nA. Thiamine, B. Riboflavin, C. Vitamin E, D. Vit K', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Biological active form is Thiamine pyrophosphate (TPP). Acts as a coenzyme in several metabolic reactions. * Acts as coenzyme to the enzyme pyruvate dehydrogenase complex (PDH) which conves pyruvic acid to acetyl-CoA (oxidative decarboxylation) Pyruvate PDH TPP Acetyl-CoA * Similarly acts as a coenzyme to a-oxoglutarate dehydrogenase complex and conves a-oxoglutarate to succinyl-CoA (oxidative decarboxylation). a-oxoglutarate dehydrogenase a-Oxoglutarate TPP Succinyl-CoARef: MN Chatterjea Textbook of Medical Biochemistry, 6th Edition, Page no: 178', 'role': 'assistant'}]