Amongst a wide variety of different biochemical reactions in cellular car-bon metabolism, thiamin diphosphate-dependent enzymes catalyze the oxi-dative decarboxylation of 2-keto acids. This type of reaction typically involves redox coupled acyl transfer to CoA or phosphate and is mediated by additional cofactors, such as flavins, iron-sulfur clusters or lipoamide swinging arms, which transmit the reducing equivalents that arise during keto acid oxidation to a final electron acceptor.
