2-oxoisovalerate dehydrogenase subunit alpha, mitochondrial (BCKDHA) (BCKDHA)

2-oxoisovalerate dehydrogenase subunit alpha, mitochondrial (BCKDHA) is a key component of the branched-chain alpha-keto acid dehydrogenase (BCKD) complex, which resides in the mitochondrial matrix (UniProt P12694). This enzyme catalyzes the rate-limiting oxidative decarboxylation of branched-chain alpha-keto acids derived from the essential amino acids leucine, isoleucine, and valine (NCBI Gene ID: 593). BCKDHA specifically encodes the alpha subunit of the E1 decarboxylase component, which requires thiamine pyrophosphate as a cofactor for its catalytic activity (StatPearls: Maple Syrup Urine Disease). Mutations in BCKDHA lead to Maple Syrup Urine Disease (MSUD) Type IA, a condition where the inability to break down branched-chain amino acids results in toxic accumulation, causing severe neurological damage and metabolic crises. In clinical practice, BCKDHA is targeted indirectly by drugs like sodium phenylbutyrate, which inhibits the BCKD kinase (BCKDK), thereby preventing the phosphorylation-induced inactivation of the BCKD complex and enhancing residual enzyme activity (PMID: 21333905). Additionally, thiamine supplementation is used in thiamine-responsive variants of MSUD to stabilize the E1 subunit and improve metabolic flux. Recent studies also highlight the role of BCKDHA in cancer metabolism and insulin resistance, suggesting its potential as a broader therapeutic target in metabolic diseases.

Other names

Branched-chain alpha-keto acid dehydrogenase E1 component subunit alphaBCKDE1A2-oxoisovalerate dehydrogenase (lipoamide) complex, E1 component alpha polypeptideBCKDH E1-alpha

Cofactor-mediated stabilization of the E1 subunit and reduction of inhibitory phosphorylation via BCKDK inhibition to enhance enzymatic flux.