Uridine (UR)

Uridine, a nucleoside, contains an uracil attached to a ribose ring (known as a ribofuranose) via a β-N1-glycosidic bond. If uracil is attached to a deoxyribose ring, it is known as a deoxyuridine. Uridine plays a role in the glycolysis pathway of galactose. There is no catabolic process to metabolize galactose. Therefore, galactose is converted to glucose and metabolized in the common glucose pathway. Once the incoming galactose has been converted into galactose-1-phosphate (Gal-1-P), it is involved in a reaction with UDP-glucose, a glucose molecule bonded to a UDP (uridine-di-phosphate) molecule. This process is catalyzed by the enzyme galactose-1-phosphate uridyl transferase, and transfers the UDP to the galactose molecule. The end result is a UDP-galactose molecule and a glucose-1-phosphate molecule. This process is continued to allow the proper glycolysis of the galactose molecule.