Reaction: UDP-N-acetyl-α-D-galactosamine + N-acetyl-β-D-glucosaminyl group = UDP + N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl group
Glossary: N,N'-diacetyllactosediamine = N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-D-glucosamine
Other name(s): β1,4-N-acetylgalactosaminyltransferase III; β4GalNAc-T3; β1,4-N-acetylgalactosaminyltransferase IV; β4GalNAc-T4; UDP-N-acetyl-D-galactosamine:N-acetyl-β-D-glucosaminyl-group β-1,4-N-acetylgalactosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-galactosamine:N-acetyl-β-D-glucosaminyl-group β-1,4-N-acetylgalactosaminyltransferase
Comments: The enzyme from human can transfer N-acetyl-D-galactosamine (GalNAc) to N-glycan and O-glycan substrates that have N-acetyl-D-glucosamine (GlcNAc) but not D-glucuronic acid (GlcUA) at their non-reducing end. The N-acetyl-β-D-glucosaminyl group is normally on a core oligosaccharide although benzyl glycosides have been used in enzyme-characterization experiments. Some glycohormones, e.g. lutropin and thyrotropin contain the N-glycan structure containing the N-acetyl-β-D-galactosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl group.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Sato, T., Gotoh, M., Kiyohara, K., Kameyama, A., Kubota, T., Kikuchi, N., Ishizuka, Y., Iwasaki, H., Togayachi, A., Kudo, T., Ohkura, T., Nakanishi, H. and Narimatsu, H. Molecular cloning and characterization of a novel human β1,4-N-acetylgalactosaminyltransferase, β4GalNAc-T3, responsible for the synthesis of N,N'-diacetyllactosediamine, GalNAc β1-4GlcNAc. J. Biol. Chem. 278 (2003) 47534-47544. [PMID: 12966086]
2. Gotoh, M., Sato, T., Kiyohara, K., Kameyama, A., Kikuchi, N., Kwon, Y.D., Ishizuka, Y., Iwai, T., Nakanishi, H. and Narimatsu, H. Molecular cloning and characterization of β1,4-N-acetylgalactosaminyltransferases IV synthesizing N,N'-diacetyllactosediamine. FEBS Lett. 562 (2004) 134-140. [PMID: 15044014]