-Ureidopropionic Acid

-Ureidopropionic acid is an intermediate in pyrimidine nucleotide catabolism. Nucleoside phosphorylases act, as shown here to yield a base and ribose-1-phosphate. If bases or nucleosides are not reused for nucleic acid synthesis via salvage pathways, the bases are further degraded to uric acid (purines) or -ureidopropionate (pyrimidines).

> 1. Dihydrouracil + H 2O <=> -Ureidopropionic Acid (catalyzed by Hydropyrimidine Hydratase)

> 2. -Ureidopropionic Acid + H 2 O <=> Alanine + NH 4+ + CO 2 (catalyzed by -Ureidopropionase)

See also: Figure 22.11, Pyrimidine Catabolism

INTERNET LINK: Pyrimidine Metabolism