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Identification of the catalytic glutamate in the E1 component of human pyruvate dehydrogenase
Author(s) -
Fang Rui,
Nixon Peter F.,
Duggleby Ronald G.
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01249-6
Subject(s) - pyruvate dehydrogenase complex , thiamine , cofactor , pyruvate dehydrogenase phosphatase , alanine , biochemistry , chemistry , glutamine , glutamate receptor , pyruvate decarboxylation , residue (chemistry) , glutamate dehydrogenase , dihydrolipoyl transacetylase , pyruvate dehydrogenase kinase , protein subunit , enzyme , amino acid , receptor , gene
The pyruvate dehydrogenase complex catalyzes the conversion of pyruvate to acetyl‐CoA. The first component (E1) converts pyruvate to bound acetaldehyde using thiamine diphosphate (ThDP) and Mg 2+ as cofactors. There is no 3D structure of E1 available but those of other ThDP‐dependent enzymes show some similarities including a glutamate residue that assists in ThDP activation. Eukaryotic E1 has an α 2 β 2 structure and the conserved Glu 89 of the β‐subunit was identified as a possible catalytic residue by sequence alignment. Human E1 was expressed in Escherichia coli and purified. Mutating Glu 89 to glutamine, aspartate and alanine markedly reduces catalytic activity and the affinity for ThDP, consistent with a role as the catalytic glutamate.