InterPro domain: IPR027110

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) [ 1 ]. 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 [ 2 ]. Some bacteria also have E1 alpha and E1 beta subunits, found as a heterodimer of an alpha and a beta chain [ 3 ].

Defects in PDHB are the cause of pyruvate dehydrogenase E1-beta deficiency (PDHBD), an enzymatic defect causing primary lactic acidosis in children [ 4 ].

1. Characterization of PDH beta 1, the structural gene for the pyruvate dehydrogenase beta subunit from Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. U.S.A. 90, 1252-6
2. Structural basis for flip-flop action of thiamin pyrophosphate-dependent enzymes revealed by human pyruvate dehydrogenase. J. Biol. Chem. 278, 21240-6
3. Purification of the pyruvate dehydrogenase multienzyme complex of Zymomonas mobilis and identification and sequence analysis of the corresponding genes. J. Bacteriol. 180, 1540-8
4. Mutations in the gene for the E1beta subunit: a novel cause of pyruvate dehydrogenase deficiency. Hum. Genet. 115, 123-7