The PCCA gene localizes to the chromosomal region 13q32.3. It gives instructions for making the alpha subunit of the heterodimeric mitochondrial Propionyl-CoA Carboxylase enzyme. This enzyme comprises 728 amino acids and weighs approximately 80 kDa. Propionyl-CoA Carboxylase enzyme plays a role in breaking down several amino acids including: isoleucine, methionine, threonine, and valine. The alpha subunit includes the biotin-binding region of this enzyme that binds to biotin and uses it to convert the propionyl-CoA to methylmalonyl-CoA.
Defects in the Propionyl-CoA Carboxylase enzyme results in the accumulation of harmful compounds that build up to toxic levels in the body, causing damages resulting in propionic academia. Propionic Acidemia is a life-threatening disease, characterized by episodic vomiting, lethargy and ketosis, neutropenia, periodic thrombocytopenia, hypogammaglobulinemia, developmental retardation, and intolerance to protein.