Pyruvate dehydrogenase complex and α-ketoglutarate dehydrogenase complex (PDC and OGDH (or PDHc and OGDHc))

Pyruvate dehydrogenase complex (PDHc, or PDC) and α-ketoglutarate dehydrogenase complex (OGDHc) are large, multi-enzyme assemblies located in the mitochondrial matrix, catalyzing two pivotal, irreversible enzymatic steps of central carbon metabolism. PDHc catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA, linking glycolysis to the TCA (citric acid) cycle and enabling aerobic energy production, biosynthesis, and acetyl-CoA–dependent cellular processes[1][2][4][5]. OGDHc catalyzes the conversion of α-ketoglutarate to succinyl-CoA within the TCA cycle, also producing NADH[4]. Both complexes are built from multiple copies of three core enzymes: E1 (dehydrogenase, ThDP-dependent), E2 (dihydrolipoamide acyltransferase), and E3 (dihydrolipoamide dehydrogenase)[2][5]. Their activity is tightly regulated via phosphorylation (PDC), allosteric feedback, and by metabolic state sensors. Dysfunction of these complexes is implicated in a range of human diseases, particularly those affecting highly aerobic tissues[4][5]. Both are emerging as therapeutic targets, notably in cancer and rare mitochondrial disorders, and their activity can be specifically modulated pharmacologically.

Other names

Pyruvate dehydrogenase (for PDC/E1 component)PDHPDHc2-oxoglutarate dehydrogenaseα-ketoglutarate dehydrogenaseOGDHOGDHc2-oxoglutarate dehydrogenase complexPyruvate dehydrogenase (acetyl-transferring)PDCα-KGDH

Allosteric modulators: e.g., product inhibition by NADH, acetyl-CoA, succinyl-CoA; Phosphorylation/dephosphorylation: Inactivation/activation of PDC via PDK/PDP (pyruvate dehydrogenase kinase/phosphatase); Enzyme inhibition: Direct binding or covalent modification of E1 or E2 components (e.g., arsenic trioxide binds lipoic acid); Substrate-level competition (e.g., thiamine deficiency reduces catalytic activity)