The pyruvate dehydrogenase complex catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and thereby links the glycolytic pathway to the tricarboxylic cycle. (R)-N(6)-dihydrolipoyl-L-lysyl-[protein] + acetyl-CoA = (R)-N(6)-(S(8)-acetyldihydrolipoyl)-L-lysyl-[protein] + CoA Binds 1 lipoyl cofactor covalently. Part of the multimeric pyruvate dehydrogenase complex that contains multiple copies of pyruvate dehydrogenase (subunits PDH1A and PDHB, E1), dihydrolipoamide acetyltransferase (DLAT, E2) and lipoamide dehydrogenase (DLD, E3). These subunits are bound to an inner core composed of about 48 DLAT and 12 PDHX molecules. Interacts with PDK2 and PDK3. Interacts with SIRT4. Interacts with PDHB. Expressed in flagella of epididymal sperm. Delipoylated at Lys-123 and Lys-249 by SIRT4, delipoylation decreases the PHD complex activity. Primary biliary cirrhosis (PBC) is an autoimmune disease characterized by inflammatory obliteration of intra-hepatic bile duct, leading to liver cell damage and cirrhosis. The E2 component of pyruvate dehydrogenase complex is the autoantigen for PBC. Belongs to the 2-oxoacid dehydrogenase family.