Sequence conservation in the α and β subunits of pyruvate dehydrogenase and its similarity to branched‐chain α‐keto acid dehydrogenase

Abstract

Amino acid sequence comparison of 8α and 6β subunits of the α-keto acid dehydrogenase (E₁) component of the pyruvate dehydrogenase complex and branched-chain α-keto acid dehydrogenase complex from multiple species was performed by computer analysis. In addition to 2 previously recognized regions of homology in the α subunit, a 3rd region of extensive homology was identified in E₁α, and may be one of the sites involved in subunit interaction. E₁β contains 4 regions of extensive homology. Region 1 contains 10 amino acids that are homologous to a 10-amino acid stretch in Escherichia coli E₁. Regions 2 and 3 have sequence homologies with other dehydrogenases suggesting that these regions may be involved in catalysis.