IUBMB Enzyme Nomenclature

EC 2.4.99.18

Accepted name: dolichyl-diphosphooligosaccharide—protein glycotransferase

Reaction: dolichyl diphosphooligosaccharide + [protein]-L-asparagine = dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-β-D-glycosyl linkage to a protein L-asparagine

For diagram of reaction click here.

Other name(s): dolichyldiphosphooligosaccharide-protein glycosyltransferase; asparagine N-glycosyltransferase; dolichyldiphosphooligosaccharide-protein oligosaccharyltransferase; dolichylpyrophosphodiacetylchitobiose-protein glycosyltransferase; oligomannosyltransferase; oligosaccharide transferase; dolichyldiphosphoryloligosaccharide-protein oligosaccharyltransferase; dolichyl-diphosphooligosaccharide:protein-L-asparagine oligopolysaccharidotransferase; STT3

Systematic name: dolichyl-diphosphooligosaccharide:protein-L-asparagine N-β-D-oligopolysaccharidotransferase

Comments: Occurs in eukaryotes that form a glycoprotein by the transfer of a glucosyl-mannosyl-glucosamine polysaccharide to the side-chain of an L-asparagine residue in the sequence -Asn-Xaa-Ser- or -Asn-Xaa-Thr- (Xaa not Pro) in nascent polypeptide chains. The basic oligosaccharide is the tetradecasaccharide Glc3Man9GlcNAc2 (for diagram click here). However, smaller oligosaccharides derived from it and oligosaccharides with additional monosaccharide units attached may be involved. See ref [2] for a review of N-glycoproteins in eukaryotes. Man3GlcNAc2 seems to be common for all of the oligosaccharides involved with the terminal N-acetylglucosamine linked to the protein L-asparagine. Occurs on the cytosolic face of the endoplasmic reticulum. The dolichol involved normally has 14-21 isoprenoid units with two trans double-bonds at the ω end, and the rest of the double-bonds in cis form.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 75302-32-8

References:

1. Das, R.C. and Heath, E.C. Dolichyldiphosphoryloligosaccharide-protein oligosaccharyltransferase; solubilization, purification, and properties. Proc. Natl. Acad. Sci. USA 77 (1980) 3811-3815. [PMID: 6933437]

2. Song, W., Henquet, M.G., Mentink, R.A., van Dijk, A.J., Cordewener, J.H., Bosch, D., America, A.H. and van der Krol, A.R. N-glycoproteomics in plants: perspectives and challenges. J Proteomics 74 (2011) 1463-1474. [PMID: 21605711]

[EC 2.4.99.18 created 1984 as EC 2.4.1.119, transferred 2012 to EC 2.4.99.18]


Return to EC 2.4.99 home page
Return to EC 2.4 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page