Biochemistry Irreversible step in citric acid cycle is catalyzed by ? A Aconitase B Succinate thiokinase C a-ketoglutarate dehydrogenase D Isocitrate dehydrogenase 💡 Explanation Irreversible step in citric acid cycle is catalyzed by ? ✓ Correct Answer: C. a-ketoglutarate dehydrogenase