Proteins in this family are E1 beta subunit (also known as PDB1 or PDHB) of the pyruvate dehydrogenase (PDH) complex. This PDH complex catalyses the overall conversion of pyruvate to acetyl-CoA and CO2. It contains multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and lipoamide dehydrogenase (E3) []. In mitochondria the E1 enzyme exists as a heterotetramer of two E1 alpha subunits and two E1 beta subunits, with thiamine pyrophosphate as a cofactor []. Some bacteria also have E1 alpha and E1 beta subunits, found as a heterodimer of an alpha and a beta chain [].Defects in PDHB are the cause of pyruvate dehydrogenase E1-beta deficiency (PDHBD), an enzymatic defect causing primary lactic acidosis in children [].
