Secondary research leads were compared with the immutable UniProt record and primary abstracts. The provider report itself was preserved, and its bibliographic inventory was not independently verified.

Human E1 has an alpha2-beta2 architecture with shared cofactor sites and structural potassium in both subunits. This is the E1 structure, not a structure of the entire multienzyme complex.

Mutagenesis of His146-beta in the paper numbering supports a direct catalytic contribution to reductive acylation. The alpha histidine has a distinct structural role; no precursor-coordinate conversion is asserted.

ThDP binding and alpha-chain phosphorylation-loop conformation are coupled within assembled human E1; this does not assign kinase or phosphatase activity to BCKDHB.

Alpha-chain phosphorylation inhibits assembled E1 through changes affecting reductive acylation. This is complex regulation rather than beta-chain phosphorylation activity.

A familial leader-region frameshift is associated with absence of E1-beta, reduced E1-alpha and approximately 6% residual complex activity. The sequence defect is not an isolated import assay, and the cached Full Text section repeats the abstract.

The human interaction screen supplies the curator-attributed BCKDHB association with P12694. The individual supplementary assay record was not inspected; assembled E1 evidence independently supports the association without establishing direct affinity in this screen.

The human interactome study supplies a curator-attributed P12694 association. The exact supplementary pair record was not independently inspected, and association is not equated with a measured direct binding affinity.

A quantitative human mitochondrial proteomics study supplies the mitochondrial annotation. The specific BCKDHB supplementary row was not inspected in this consultation.

Purified human liver BCKDH complex oxidizes branched-chain ketoacids derived from all three branched-chain amino acids. The complete-complex reaction does not assign downstream acyl-CoA synthesis autonomously to the beta chain.

Human E1 chains expressed in a bacterial chaperonin system form an alpha2-beta2 enzyme; alpha-chain disease mutations impair assembly. The alpha-focused disease context does not exclude experimental observation of the beta-containing enzyme.

BCKDK phosphorylates and inhibits the BCKDH complex. BCKDHA is the regulated alpha subunit; being the substrate of a kinase does not assign kinase activity to either E1 chain.

The normal summary calls the dephosphorylated target E1 beta. This conflicts with the alpha phosphorylation loop characterized in PMID:15166214 and PMID:15576032 and the reviewed alpha-chain UniProt record. Flag that subunit wording as disputed while preserving the machine source unchanged. PPM1K supplies phosphatase activity; neither E1 chain is a phosphatase. The discrepancy does not refute the independently supported matrix localization.

The human alpha2-beta2 E1 tetramer decarboxylates the three branched-chain ketoacids and reductively acylates the DBT lipoyl group. The two ThDP molecules and four potassium ions describe the assembled tetramer. Individual coordinating residues are not separate ion sites, and the summary does not establish catalysis by isolated alpha or beta.

The body describes DBT transfer of branched-chain acyl groups from its lipoyl group to CoA; the abbreviated BCAA title should not be read as direct amino-acid transfer. This is E2 chemistry downstream of the E1 reaction, not autonomous CoA-transfer activity of BCKDHA or BCKDHB.

DLD reoxidizes reduced lipoyl groups through FAD and transfers reducing equivalents to NAD+, producing NADH. The event provides complex context and does not assign E3 redox chemistry, NAD binding or reactive-oxygen production to either E1 chain.

The event concerns loss-of-function DBT variants and impaired acyl transfer. It is disease context for the shared complex, not evidence that wild-type E1 lacks activity or localization, or that the E1 chains perform the DBT reaction.

The event describes BCKDHA or BCKDHB variants that destabilize E1 assembly and impair the complex. Severe residual-activity values are genotype-specific, not a universal property of every variant. In particular, they do not override the approximately 6% residual complex activity described for the family in PMID:2022752.

The record concerns DLD loss-of-function variants and defective lipoyl reoxidation. DLD disease mechanisms and its roles in other complexes are not independent functions of BCKDHA or BCKDHB.

BCKDK loss removes inhibitory phosphorylation of BCKDHA, leaving BCKDH insufficiently restrained and depleting branched-chain amino acids. It is a kinase-deficiency mechanism, not E1 loss of function or evidence that the E1 subunits catalyze phosphorylation.

The event describes a truncated PPM1K variant associated with impaired BCKDH dephosphorylation. It supplies regulator and disease context without assigning phosphatase activity to either E1 chain.

The immutable human record identifies precursor Tyr152 as a ThDP contact shared with alpha and six potassium-coordinating positions. Its two explicit alternative products are retained without RefSeq-numbering equivalence.

The precursor residue152 feature records thiamine diphosphate contact shared with the alpha subunit. The record assigns mitochondrial matrix localization and EC1.2.4.4 to assembled E1, and describes the DBT24-mer core architecture.