Branched-chain amino acids metabolic pathway (BCAA metabolic pathway)

The **branched-chain amino acids metabolic pathway** refers to the cellular processes in which the three proteinogenic branched-chain amino acids—leucine, isoleucine, and valine—are catabolized. This pathway is initiated by **branched-chain aminotransferase (BCAT)** enzymes (cytosolic BCAT1 and mitochondrial BCAT2), which transaminate BCAAs into branched-chain keto acids (BCKAs)[1][2][3][5]. The BCKAs are further processed by the **branched-chain α-keto acid dehydrogenase (BCKDH) complex**, an enzyme structurally similar to pyruvate dehydrogenase, converting BCKAs into acyl-CoA derivatives[1][2][3][6]. These then feed into distinct metabolic routes, ultimately yielding molecules such as acetyl-CoA and succinyl-CoA that enter the tricarboxylic acid (TCA) cycle for cellular energy production[1][2][3][6]. This pathway’s dysfunction is implicated in diseases like obesity and type 2 diabetes by disturbing glucose and lipid metabolism[2][3][7]. Regulation occurs through kinases such as BCKDK, affected by nutrient and hormonal signals, linking BCAA metabolism to whole-body energy homeostasis[2][3]. **Critical note:** The term “Branched-chain amino acids metabolic pathway” describes a pathway—not a discrete molecular target (receptor, enzyme, transporter). Individual enzymes within the pathway (e.g., BCAT1, BCAT2, BCKDH complex) may be considered therapeutic molecular targets, but the pathway itself is not targeted directly by drugs. Therefore, “is_target” is false and “is_incorrect” is true from a drug-target annotation perspective.

Other names

Branched-chain amino acid catabolismBCAA catabolismBranched-chain amino acid degradation pathway