The branched chain α- keto acid dehydrogenase complex resides in the inner membrane of mitochondria. It is a multi-sub unit complex of the enzymes. The action of this enzyme results in oxidative decarboxylation of short and branched α- keto acid.

The α- keto acid dehydrogenase enzyme family consists of α- ketoglutarate dehydrogenase and pyruvate dehydrogenase enzymes. These two enzymes are important for Krebs cycle. The three catalytic components of this enzyme are denoted as E₁, E₂ and E₃. The E₁ component is α- keto acid dehydrogenase, E₂component is dihydrolipoyl transacylase and the E₃ component is dihydrolipoamide dehydrogenase.

When branched chain α- keto acid dehydrogenase complex acts on citrate, the reaction product will be as follows: