Target type: molecularfunction
Catalysis of the reaction: beta-D-galactosyl-(1,4)-beta-N-acetyl-D-glucosaminyl-R + UDP-galactose = alpha-D-galactosyl-(1,3)-beta-D-galactosyl-(1,4)-beta-N-acetyl-D-glucosaminyl-R + UDP. [EC:2.4.1.87, MetaCyc:2.4.1.87-RXN, RHEA:13013]
N-acetyllactosaminide 3-alpha-galactosyltransferase activity is a crucial enzyme in the biosynthesis of glycoconjugates, particularly those containing the Galbeta1-4GlcNAc (LacNAc) disaccharide. This enzyme catalyzes the transfer of a galactose residue from a donor substrate, typically UDP-galactose, to the 3-hydroxyl group of the N-acetylglucosamine (GlcNAc) moiety in LacNAc. The resulting product is Galbeta1-3Galbeta1-4GlcNAc, which is a common structural element found in various glycoproteins and glycolipids.
This enzymatic activity plays a vital role in the synthesis of complex carbohydrates, such as the N-glycans and O-glycans that decorate cell surface proteins and lipids. These glycoconjugates are involved in numerous biological processes, including cell-cell interactions, immune recognition, and signal transduction.
Specifically, N-acetyllactosaminide 3-alpha-galactosyltransferase activity contributes to the formation of diverse glycosphingolipids, which are critical components of cellular membranes. These glycosphingolipids are involved in cell adhesion, cell migration, and the regulation of cellular signaling pathways.
Moreover, this enzyme activity is essential for the biosynthesis of various glycoproteins, including those involved in blood group antigens, immunoglobulins, and hormones.
In summary, N-acetyllactosaminide 3-alpha-galactosyltransferase activity is a key enzymatic process that contributes to the generation of a wide range of glycoconjugates with diverse biological roles. Its function is essential for maintaining cellular integrity, regulating cell-cell interactions, and orchestrating crucial signaling pathways within the organism.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| N-acetyllactosaminide alpha-1,3-galactosyltransferase | An N-acetyllactosaminide alpha-1,3-galactosyltransferase that is encoded in the genome of cow. [OMA:P14769, PRO:DNx] | 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 |