Reaction: UDP-α-D-galactose + β-D-galactosyl-(1→4)-β-N-acetyl-D-glucosaminyl-R = UDP + α-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-N-acetylglucosaminyl-R
(where R can be OH, an oligosaccharide or a glycoconjugate)
Other name(s): α-galactosyltransferase; UDP-Gal:β-D-Gal(1,4)-D-GlcNAc α(1,3)-galactosyltransferase; UDP-Gal:N-acetyllactosaminide α(1,3)-galactosyltransferase; UDP-Gal:N-acetyllactosaminide α-1,3-D-galactosyltransferase; UDP-Gal:Galβ1→4GlcNAc-R α1→3-galactosyltransferase; UDP-galactose-acetyllactosamine α-D-galactosyltransferase; UDPgalactose:β-D-galactosyl-β-1,4-N-acetyl-D-glucosaminyl-glycopeptide α-1,3-D-galactosyltransferase; glucosaminylglycopeptide α-1,3-galactosyltransferase; uridine diphosphogalactose-acetyllactosamine α1→3-galactosyltransferase; uridine diphosphogalactose-acetyllactosamine galactosyltransferase; uridine diphosphogalactose-galactosylacetylglucosaminylgalactosylglucosylceramide galactosyltransferase; β-D-galactosyl-N-acetylglucosaminylglycopeptide α-1,3-galactosyltransferase; UDP-galactose:N-acetyllactosaminide 3-α-D-galactosyltransferase; UDP-galactose:β-D-galactosyl-1,4-β-N-acetyl-D-glucosaminyl-R 3-α-D-galactosyltransferase; UDP-galactose:β-D-galactosyl-(1→4)-β-N-acetyl-D-glucosaminyl-R 3-α-D-galactosyltransferase
Systematic name: UDP-α-D-galactose:β-D-galactosyl-(1→4)-β-N-acetyl-D-glucosaminyl-R 3-α-D-galactosyltransferase
Comments: Acts on β-galactosyl-1,4-N-acetylglucosaminyl termini on asialo-α1-acid glycoprotein and N-acetyllactosamine (β-D-galactosyl-1,4-N-acetyl-β-D-glucosamine), but not on 2'-fucosylated-N-acetyllactosamine. The non-reducing terminal N-acetyllactosamine residues of glycoproteins can also act as acceptor. Now includes EC 2.4.1.124 and EC 2.4.1.151.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 128449-51-4
References:
1. Basu, M. and Basu, S. Enzymatic synthesis of a blood group B-related pentaglycosylceramide by an α-galactosyltransferase from rabbit bone marrow. J. Biol. Chem. 248 (1973) 1700-1706. [PMID: 4632915]
2. Blanken, W.M. and van den Eijnden, D.H. Biosynthesis of terminal Gal α1→3Gal β1→4GlcNAc-R oligosaccharide sequences on glycoconjugates. Purification and acceptor specificity of a UDP-Gal:N-acetyllactosaminide α1→3-galactosyltransferase from calf thymus. J. Biol. Chem. 260 (1985) 12927-12934. [PMID: 3932335]
3. Blake, D.A. and Goldstein, I.J. An α-D-galactosyltransferase activity in Ehrlich ascites tumor cells. Biosynthesis and characterization of a trisaccharide (α-D-galactose-(1→3)-N-acetyllactosamine). J. Biol. Chem. 256 (1981) 5387-5393. [PMID: 6787040]