Overview Other names Krebs cycle, tricarboxylic acid (TCA) cycle Function generate high amounts of NADH/FADH2 that act as fuel for ATP synthesis in the electron transport chain Pathway occurs in the mitochondria requires O2 to function net equation acetyl-CoA + 3 NAD+ + FAD + GDP + Pi → 2CO2 + 3 NADH + FADH2 + GTP + CoA will theoretically yield 12 ATP (if ETC were 100% efficient) both carbons of acetyl-CoA leave as CO2 in two of the reactions conversion of isocitrate to alpha ketoglutarate conversion of alpha ketoglutarate to succinyl-CoA Important enzymes isocitrate dehydrogenase stimulated by ↓ energy ↑ ADP inhibited by ↑ energy ↑ ATP, NADH α-ketoglutarate dehydrogenase complex requires the same cofactors as the pyruvate dehydrogenase complex B1, B2, B3, B5, lipoic acid in alcoholics, B1 deficiency leads to Wernicke's encephalopathy triad of ataxia, confusion, ophthalmoplegia inhibited by ↑ energy ↑ ATP, NADH inhibited by ↑ intermediates in the cycle ↑ succinyl-CoA succinyl-CoA synthetase generates GTP succinate dehydrogenase a member of both the citric acid cycle and the electron transport chain important intermediates citrate functions to shuttle acetyl-CoA out of mitochondria for fatty acid synthesis citrate shuttle succinyl-CoA building block for heme synthesis fumarate enters from the urea cycle malate functions as a gluconeogenic substrate Regulation energy status control NO hormonal control