Branched-chain alpha-keto acid dehydrogenase E1 component beta subunit (BCKDHB)

The **branched-chain alpha-keto acid dehydrogenase E1 component beta subunit (BCKDHB)** is one of the essential protein subunits forming the E1 component of the mitochondrial branched-chain alpha-keto acid dehydrogenase (BCKD) complex, a key multienzyme complex responsible for the *oxidative decarboxylation* of the branched-chain amino acids—*leucine*, *isoleucine*, and *valine*—in human metabolism. The E1 component is a heterotetramer composed of two alpha (BCKDHA) and two beta (BCKDHB) subunits. BCKDHB mutations cause a deficiency in the BCKD complex, resulting in the rare but severe metabolic disorder **maple syrup urine disease (MSUD)**, typified by the toxic accumulation of branched-chain amino acids and their keto acids in the body. This disease manifests with neurological dysfunction and, if not treated, can be fatal. Currently, no approved drugs target BCKDHB directly; standard management includes rigorous dietary control to limit intake of the implicated amino acids and supportive management during metabolic stress[1][2][3][4].

Other names

Branched chain keto acid dehydrogenase E1 subunit beta2-oxoisovalerate dehydrogenase subunit beta, mitochondrialBCKDE1BBCKDH E1-betaBranched-chain alpha-keto acid dehydrogenase E1 component beta chainBranched chain keto acid dehydrogenase E1, beta polypeptideOVD1BE1b-beta subunit of the branched-chain complexEC 1.2.4.4Branched chain alpha-ketoacid dehydrogenase E1-beta subunit

Drugs could potentially act by modulating enzymatic activity or stability, but current clinical management relies on dietary restriction of branched-chain amino acids and supportive therapy[1][2][4].