Category: catabolism
Mitochondrial 8-enzyme cycle oxidizing acetyl-CoA to 2 CO2 with reduction of 3 NAD+ + 1 FAD + 1 GDP → ATP-equivalents that drive the electron transport chain. Citrate synthase condenses acetyl-CoA + oxaloacetate; aconitase isomerizes; isocitrate dehydrogenase (rate-limiting, NAD-linked) + α-ketoglutarate dehydrogenase + succinyl-CoA synthetase + succinate dehydrogenase (also Complex II of ETC) + fumarase + malate dehydrogenase complete the cycle. Anaplerotic refilling primarily from pyruvate carboxylase (pyruvate → oxaloacetate) maintains intermediate pool during high biosynthesis demand.