Uridine diphosphate galactose

Uridine diphosphate galactose (often abbreviated as UDP-galactose) is a nucleotide sugar. It is used in metabolism as a glycosyl donor to create glycosidic bonds. UDP-galactose is involved in the biosynthesis of glycoproteins and glycolipids.

Structure and Properties

UDP-galactose is composed of a uridine diphosphate (UDP) and a galactose sugar. The UDP component is made up of a uridine molecule (a nucleoside consisting of uracil attached to a ribose sugar) and two phosphate groups. The galactose sugar is attached to the UDP via a glycosidic bond.

Biosynthesis

UDP-galactose is synthesized from UDP-glucose by the enzyme UDP-glucose 4-epimerase. This reaction is reversible, allowing for the interconversion of UDP-glucose and UDP-galactose.

Function

UDP-galactose serves as a glycosyl donor in the biosynthesis of glycoproteins and glycolipids. It is used by glycosyltransferase enzymes to transfer a galactose sugar to specific acceptor molecules, forming a glycosidic bond.

Clinical Significance

Deficiencies in the enzyme UDP-glucose 4-epimerase can lead to a rare genetic disorder known as Galactosemia, which results in an inability to properly metabolize galactose. This can lead to a buildup of galactose and its derivatives, including UDP-galactose, in the body.

See Also

• Uridine diphosphate glucose
• Uridine diphosphate
• Galactose
• Galactosemia