A multimer (24-mer) of this enzyme forms the core of the multienzyme complex, and binds tightly both EC
1.2.4.2, oxoglutarate dehydrogenase (succinyl-transferring) and EC
1.8.1.4, dihydrolipoyl dehydrogenase. The lipoyl group of this enzyme is reductively succinylated by EC
1.2.4.2, and the only observed direction catalysed by EC
2.3.1.61 is that where this succinyl group is passed to coenzyme A.