beta -Ureidopropionase is a cytoplasmic protein which belongs to the CN hydrolase family of BUP subfamily. beta -Ureidopropionase binds one zinc ion per subunit, catalyzes the last step in the pyrimidine degradation pathway. beta -Ureidopropionase can convert N-carbamyl-beta-aminoisobutyric acid and N-carbamyl-beta-alanine to beta-aminoisobutyric acid and beta-alanine, ammonia and carbon dioxide, respectively. The pyrimidine bases uracil and thymine are degraded via the consecutive action of dihydropyrimidine dehydrogenase (DHPDH), dihydropyrimidinase (DHP) and beta-ureidopropionase (UP) to beta-alanine and beta aminoisobutyric acid, respectively. Defects in beta -Ureidopropionase are the cause of beta -Ureidopropionase deficiency that is characterized by muscular hypotonia, dystonic movements, scoliosis, microcephaly and severe developmental delay.