Target type: molecularfunction
Catalysis of the transfer of a galactose group from UDP-galactose to an acceptor molecule. [PMID:19858195]
UDP-galactosyltransferase activity is a crucial enzymatic process involved in the transfer of galactose from UDP-galactose (UDP-Gal) to an acceptor molecule, typically a hydroxyl group on a sugar or lipid. This transfer reaction plays a vital role in the biosynthesis of various complex carbohydrates, glycolipids, and glycoproteins.
The enzyme UDP-galactosyltransferase (GalT) catalyzes the formation of a glycosidic bond between the galactose moiety of UDP-Gal and the acceptor molecule, resulting in the addition of a galactose residue to the substrate.
GalT enzymes are highly specific for both the donor substrate (UDP-Gal) and the acceptor molecule. Different GalT isoforms exhibit distinct substrate specificities, enabling the synthesis of a wide range of galactosylated products.
The molecular function of UDP-galactosyltransferase activity can be summarized as follows:
* **Galactose Transfer:** Transferring a galactose unit from UDP-Gal to an acceptor molecule.
* **Glycosidic Bond Formation:** Catalyzing the formation of a glycosidic bond between the galactose and the acceptor molecule.
* **Substrate Specificity:** Exhibiting high specificity for both UDP-Gal and the acceptor molecule.
* **Biosynthesis of Complex Carbohydrates:** Participating in the biosynthesis of various complex carbohydrates, including glycolipids and glycoproteins.
UDP-galactosyltransferase activity is essential for diverse biological processes, including:
* **Glycoprotein Synthesis:** Modifying proteins by adding galactose residues, impacting their structure, function, and interactions.
* **Glycolipid Synthesis:** Participating in the synthesis of glycolipids, which play crucial roles in cell signaling, membrane structure, and recognition.
* **Lactose Synthesis:** Catalyzing the synthesis of lactose, the primary sugar in milk, from glucose and galactose.
* **Proteoglycan Synthesis:** Involved in the synthesis of proteoglycans, complex macromolecules essential for cell adhesion, tissue structure, and signal transduction.
* **Immune Response:** Participating in immune responses by influencing the structure and function of immune cells and molecules.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Beta-1,4-galactosyltransferase 1 | [no definition available] | Bos taurus (cattle) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| uridine diphosphate galactose | UDP-alpha-D-galactose : A UDP-D-galactose in which the anomeric centre of the galactose moiety has alpha-configuration. Uridine Diphosphate Galactose: A nucleoside diphosphate sugar which can be epimerized into UDPglucose for entry into the mainstream of carbohydrate metabolism. Serves as a source of galactose in the synthesis of lipopolysaccharides, cerebrosides, and lactose. | UDP-D-galactose | mouse metabolite |