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 2 lipoyl cofactors 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) (By similarity). These subunits are bound to an inner core composed of about 48 DLAT and 12 PDHX molecules (PubMed:20361979). Interacts with PDK2 and PDK3 (By similarity). Interacts with SIRT4 (By similarity). Interacts with PDHB (By similarity). Delipoylated at Lys-5 by SIRT4, delipoylation decreases the PHD complex activity. Belongs to the 2-oxoacid dehydrogenase family.