PCCB : propionyl-CoA carboxylase subunit beta
Description
The PCCB (propionyl-CoA carboxylase subunit beta) is a protein-coding gene located on chromosome 3.
The PCCB gene provides instructions for making part of an enzyme called propionyl-CoA carboxylase, specifically, the beta subunit of this enzyme. Six beta subunits come together with six alpha subunits (produced from the PCCA gene) to form a functioning enzyme. Propionyl-CoA carboxylase plays a role in the normal processing of proteins. It carries out a particular step in the breakdown of several protein building blocks (amino acids) called isoleucine, methionine, threonine, and valine. Propionyl-CoA carboxylase also helps break down certain types of lipids (fats) and cholesterol. First, several chemical reactions convert the amino acids, lipids, or cholesterol to a molecule called propionyl-CoA. Using the B vitamin biotin, propionyl-CoA carboxylase then converts propionyl-CoA to a molecule called methylmalonyl-CoA. Additional enzymes break down methylmalonyl-CoA into other molecules that are used for energy.
PCCB, also known as Propanoyl-CoA:carbon dioxide ligase subunit beta, is part of the biotin-dependent propionyl-CoA carboxylase (PCC), a mitochondrial enzyme involved in the breakdown of odd chain fatty acids, branched-chain amino acids (isoleucine, threonine, methionine, and valine), and other metabolites. PCC catalyzes the carboxylation of propionyl-CoA/propanoyl-CoA to D-methylmalonyl-CoA/(S)-methylmalonyl-CoA. The alpha subunit of PCC catalyzes the ATP-dependent carboxylation of the biotin carried by the biotin carboxyl carrier (BCC) domain, while the beta subunit transfers the carboxyl group from carboxylated biotin to propionyl-CoA. PCC also acts on butyryl-CoA/butanoyl-CoA, converting it to ethylmalonyl-CoA/(2S)-ethylmalonyl-CoA at a lower rate. Other minor substrates include (2E)-butenoyl-CoA/crotonoyl-CoA.
PCCB is also known as -.
