A multimer (24-mer or 60-mer, depending on the source) of this enzyme forms the core of the pyruvate dehydrogenase multienzyme complex, and binds tightly both EC 184.108.40.206
, pyruvate dehydrogenase (acetyl-transferring) and EC 220.127.116.11
, dihydrolipoyl dehydrogenase. The lipoyl group of this enzyme is reductively acetylated by EC 18.104.22.168
, and the only observed direction catalysed by EC 22.214.171.124
is that where the acetyl group is passed to coenzyme A.