PDHA1 Recombinant Protein

The pyruvate dehydrogenase (PDH) complex is a nuclear-encoded mitochondrial multienzyme complex that catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and provides the primary link between glycolysis and the tricarboxylic acid (TCA) cycle. The PDH complex is composed of multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and lipoamide dehydrogenase (E3). The E1 enzyme is a heterotetramer of two alpha and two beta subunits. This gene encodes the E1 alpha 1 subunit containing the E1 active site, and plays a key role in the function of the PDH complex. Mutations in this gene are associated with pyruvate dehydrogenase E1-alpha deficiency and X-linked Leigh syndrome. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Mar 2010]

Function: The pyruvate dehydrogenase complex catalyzes the overall conversion of pyruvate to acetyl-CoA and CO2, and thereby links the glycolytic pathway to the tricarboxylic cycle. Ref.16 Ref.31

Catalytic activity: Pyruvate + [dihydrolipoyllysine-residue acetyltransferase] lipoyllysine = [dihydrolipoyllysine-residue acetyltransferase] S-acetyldihydrolipoyllysine + CO2. Ref.16 Ref.30 Ref.31

Cofactor: Thiamine pyrophosphate. Ref.28 Ref.31

Enzyme regulation: Pyruvate dehydrogenase activity is inhibited by phosphorylation of PDHA1; it is reactivated by dephosphorylation. Ref.16 Ref.30 Ref.31

Subunit structure: Heterotetramer of two PDHA1 and two PDHB subunits. The heterotetramer interacts with DLAT, and is part of the multimeric pyruvate dehydrogenase complex that contains multiple copies of pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (DLAT, E2) and lipoamide dehydrogenase (DLD, E3). These subunits are bound to an inner core composed of about 48 DLAT and 12 PDHX molecules. Ref.18 Ref.31

Subcellular location: Mitochondrion matrix.

Tissue specificity: Ubiquitous.

Post-translational modification: Phosphorylation at Ser-232, Ser-293 and Ser-300 by PDK family kinases inactivates the enzyme; for this phosphorylation at a single site is sufficient. Dephosphorylation at all three sites, i.e. at Ser-232, Ser-293 and Ser-300, is required for reactivation.

Involvement in disease: Pyruvate dehydrogenase E1-alpha deficiency (PDHAD) [MIM:312170]: An enzymatic defect causing primary lactic acidosis in children. It is associated with a broad clinical spectrum ranging from fatal lactic acidosis in the newborn to chronic neurologic dysfunction with structural abnormalities in the central nervous system without systemic acidosis.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.15 Ref.32 Ref.33 Ref.34 Ref.36 Ref.37 Ref.38 Ref.40 Ref.41 Ref.42 Ref.43 Ref.44 Ref.45 Ref.47Leigh syndrome, X-linked (X-LS) [MIM:308930]: A X-linked form of Leigh syndrome, an early-onset progressive neurodegenerative disorder characterized by the presence of focal, bilateral lesions in one or more areas of the central nervous system including the brainstem, thalamus, basal ganglia, cerebellum, and spinal cord. The lesions are areas of demyelination, gliosis, necrosis, spongiosis, or capillary proliferation. Clinical symptoms depend on which areas of the central nervous system are involved and include psychomotor retardation, hypotonia, ataxia, weakness, vision loss, eye movement abnormalities, seizures, dysphagia, and lactic acidosis.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.32 Ref.35 Ref.39 Ref.41 Ref.46

Sequence caution: The sequence AAA60055.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally shortened.The sequence AAB59581.1 differs from that shown. Reason: Frameshift at positions 106 and 175.