Irreversible step in citric acid cycle is catalyzed by ?: (A) Aconitase, (B) Succinate thiokinase, (C) a-ketoglutarate dehydrogenase, (D) Isocitrate dehydrogenase
Answer is C. Ans. is 'c' i.e., a-ketoglutarate dehydrogenase There are two irreversible steps :oxaloacetate to citrate catalysed by citrate (synthase), anda-ketoglutarate to succinyl CoA, catalyzed by a-ketoglutarate dehydrogenase.