Propionyl-CoA carboxylase beta chain (PCCB)

Propionyl-CoA carboxylase beta chain (PCCB) is one of two essential subunits forming the mitochondrial biotin-dependent enzyme propionyl-CoA carboxylase. This multimeric complex catalyzes the ATP-dependent conversion of propionyl-CoA to D-methylmalonyl-CoA—a critical step in breaking down odd-chain fatty acids and certain amino acids. The alpha subunit provides biotin binding/carboxyation activity while the beta chain contains the catalytic site responsible for transferring CO₂ from biotin to propionyl-CoA. Mutations affecting either PCCA (alpha) or PCCB (beta) genes cause autosomal recessive disorders such as propionic acidemia, characterized by severe neonatal-onset metabolic acidosis if untreated. The only current interventions involve dietary management, cofactor supplementation with biotin when responsive, organ transplantation, or experimental gene therapies[1][2][3][4].

Other names

Propionyl-CoA carboxylase subunit betaPCCBBeta subunit of propionyl-CoA carboxylase

For supportive therapies: - Biotin acts as an essential cofactor required for enzymatic activity. For gene therapy or future approaches: - Gene replacement or editing to restore functional PCCB expression.