IUBMB Enzyme Nomenclature


Accepted name: α-1,6-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase

Reaction: UDP-N-acetyl-α-D-glucosamine + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein] = UDP + β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-α-D-Man-(1→3)-[β-D-GlcNAc-(1→2)-[β-D-GlcNAc-(1→4)]-[β-D-GlcNAc-(1→6)]-α-D-Man-(1→6)]-β-D-Man-(1→4)-β-D-GlcNAc-(1→4)-β-D-GlcNAc-N-Asn-[protein]

For diagram of reaction click here.

Other name(s): MGAT4C (gene name); N-acetylglucosaminyltransferase VI; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase VI; uridine diphosphoacetylglucosamine-glycopeptide β-1→4-acetylglucosaminyltransferase VI; mannosyl-glycoprotein β-1,4-N-acetylglucosaminyltransferase; GnTVI; GlcNAc-T VI; UDP-N-acetyl-D-glucosamine:2,6-bis(N-acetyl-β-D-glucosaminyl)-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase

Systematic name: UDP-N-acetyl-α-D-glucosamine:N-acetyl-β-D-glucosaminyl-(1→6)-[N-acetyl-β-D-glucosaminyl-(1→2)]-α-D-mannosyl-glycoprotein 4-β-N-acetyl-D-glucosaminyltransferase (configuration-inverting)

Comments: Requires a high concentration of Mn2+ for maximal activity. The enzyme, characterized from hen oviduct membranes, participates in the processing of N-glycans in the Golgi apparatus. It transfers GlcNAc in β1-4 linkage to a D-mannose residue that already has GlcNAc residues attached at positions 2 and 6 by β linkages. No homologous enzyme appears to exist in mammals.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 119699-68-2


1. Brockhausen, I., Hull, E., Hindsgaul, O., Schachter, H., Shah, R.N., Michnick, S.W. and Carver, J.P. Control of glycoprotein synthesis. Detection and characterization of a novel branching enzyme from hen oviduct, UDP-N-acetylglucosamine:GlcNAc β1-6 (GlcNAc β1-2)Man α-R (GlcNAc to Man) β-4-N-acetylglucosaminyltransferase VI. J. Biol. Chem. 264 (1989) 11211-11221. [PMID: 2525556]

2. Taguchi, T., Ogawa, T., Inoue, S., Inoue, Y., Sakamoto, Y., Korekane, H. and Taniguchi, N. Purification and characterization of UDP-GlcNAc:GlcNAcβ1-6(GlcNAcβ1-2)Manα1-R [GlcNAc to Man]-β1,4-N-acetylglucosaminyltransferase VI from hen oviduct. J. Biol. Chem. 275 (2000) 32598-32602. [PMID: 10903319]

3. Sakamoto, Y., Taguchi, T., Honke, K., Korekane, H., Watanabe, H., Tano, Y., Dohmae, N., Takio, K., Horii, A. and Taniguchi, N. Molecular cloning and expression of cDNA encoding chicken UDP-N-acetyl-D-glucosamine (GlcNAc): GlcNAcβ 1-6(GlcNAcβ 1-2)- manα 1-R[GlcNAc to man]β 1,4N-acetylglucosaminyltransferase VI. J. Biol. Chem. 275 (2000) 36029-36034. [PMID: 10962001]

[EC created 1992, modified 2001, modified 2018]

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