EC	2.4.1.165
Accepted name:	N-acetylneuraminylgalactosylglucosyl-glucoside β-1,4-N-acetylgalactosaminyltransferase
Reaction:	UDP-N-acetyl-α-D-galactosamine + an α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-(1→4)-β-D-glucosyl-R = UDP + an N-acetyl-β-D-galactosaminyl-(1→4)-[α-N-acetylneuraminyl-(2→3)]-β-D-galactosyl-(1→4)-β-D-glucosyl-R
Other name(s):	B4GALNT2 (gene name); uridine diphosphoacetylgalactosamine-acetylneuraminyl(α2→3)galactosyl(β1→4)glucosyl β1→4-acetylgalactosaminyltransferase; UDP-N-acetyl-D-galactosamine:N-acetylneuraminyl-2,3-α-D-galactosyl-1,4-β-D-glucosylceramide β-1,4-N-acetylgalactosaminyltransferase (incorrect); UDP-N-acetyl-D-galactosamine:N-acetylneuraminyl-(2→3)-α-D-galactosyl-(1→4)-β-D-glucosyl(1↔1)ceramide 4-β-N-acetylgalactosaminyltransferase (incorrect); UDP-N-acetyl-D-galactosamine:N-acetylneuraminyl-(2→3)-α-D-galactosyl-(1→4)-β-D-glucosyl-(1↔1)-ceramide 4-β-N-acetylgalactosaminyltransferase (incorrect); N-acetylneuraminylgalactosylglucosylceramide β-1,4-N-acetylgalactosaminyltransferase (incorrect)
Systematic name:	UDP-N-acetyl-α-D-galactosamine:α-N-acetylneuraminyl-(2→3)-β-D-galactosyl-(1→4)-β-D-glucosyl-R 4-β-N-acetylgalactosaminyltransferase
Comments:	Requires Mn2+. The enzyme, found in mammals, is only active with substrates containing (2→3) linked sialic acid residues [2,3]. It is active with glycoproteins, but not with gangliosides. The enzyme is involved in synthesis of the blood group antigen Sda.
References:	1.  Piller, F., Blanchard, D., Huet, M. and Cartron, J.-P. Identification of a α-NeuAc-(2-3)-β-D-galactopyranosyl N-acetyl-β-D-galactosaminyltransferase in human kidney. Carbohydr. Res. 149 (1986) 171–184. [PMID: 2425965] 2.  Takeya, A., Hosomi, O. and Kogure, T. Identification and characterization of UDP-GalNAc: NeuAc α2-3Gal β1-4Glc(NAc) β1-4(GalNAc to Gal)N-acetylgalactosaminyltransferase in human blood plasma. J. Biochem. (Tokyo) 101 (1987) 251–259. [PMID: 3106337] 3.  Dohi, T., Nishikawa, A., Ishizuka, I., Totani, M., Yamaguchi, K., Nakagawa, K., Saitoh, O., Ohshiba, S. and Oshima, M. Substrate specificity and distribution of UDP-GalNAc:sialylparagloboside N-acetylgalactosaminyltransferase in the human stomach. Biochem. J. 288 (1992) 161–165. [PMID: 1445260] 4.  Montiel, M.D., Krzewinski-Recchi, M.A., Delannoy, P. and Harduin-Lepers, A. Molecular cloning, gene organization and expression of the human UDP-GalNAc:Neu5Acα2-3Galβ-R β1,4-N-acetylgalactosaminyltransferase responsible for the biosynthesis of the blood group Sda/Cad antigen: evidence for an unusual extended cytoplasmic domain. Biochem. J. 373 (2003) 369–379. [PMID: 12678917]
[EC 2.4.1.165 created 1989, modified 2025]