Pyruvate decarboxylation orpyruvate oxidation, also known as thelink reaction (oroxidative decarboxylation of pyruvate[1]), is the conversion ofpyruvate intoacetyl-CoA by the enzyme complexpyruvate dehydrogenase complex.[2][3]
The reaction may be simplified as:
Pyruvate oxidation is the step that connectsglycolysis and theKrebs cycle.[4] In glycolysis, a singleglucose molecule (6 carbons) is split into 2 pyruvates (3 carbons each). Because of this, thelink reaction occurs twice for each glucose molecule to produce a total of 2 acetyl-CoA molecules, which can then enter the Krebs cycle.
Energy-generatingions andmolecules, such asamino acids andcarbohydrates, enter the Krebs cycle as acetyl coenzyme A and oxidize in the cycle.[5] The pyruvate dehydrogenase complex (PDC) catalyzes thedecarboxylation of pyruvate, resulting in the synthesis of acetyl-CoA,CO2, andNADH. Ineukaryotes, this enzyme complex regulatespyruvate metabolism, and ensureshomeostasis of glucose during absorptive and post-absorptive state metabolism.[6] As the Krebs cycle occurs in themitochondrial matrix, the pyruvate generated duringglycolysis in thecytosol is transported across theinner mitochondrial membrane by apyruvate carrier under aerobic conditions.[citation needed]