EC - Dolichyl-P-Man:Man6GlcNAc2-PP-dolichol α-1,2-mannosyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
dolichyl-P-Man:Man6GlcNAc2-PP-dolichol α-1,2-mannosyltransferase
Other names:
ALG9 α1,2 mannosyltransferase
dolichylphosphomannose-dependent ALG9 mannosyltransferase
ALG9 mannosyltransferase
Dol-P-Man:Man6GlcNAc2-PP-Dol α-1,2-mannosyltransferase
Systematic name:
dolichyl β-D-mannosyl phosphate: D-Man-α-(1→2)-D-Man-α-(1→2)-D-Man-α-(1→3)-[D-Man-α-(1→3)-D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-1,2-mannosyltransferase



The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-dolichol to Man9Glc-NAc2-PP-dolichol on the lumenal side use dolichyl β-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different α-1,2-mannose residues - the addition of α-1,2-mannose to Man6GlcNAc2-PP-dolichol (EC and the addition of α-1,2-mannose to Man8GlcNAc2-PP-dolichol (EC

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0052926


  1. Vleugels, W., Keldermans, L., Jaeken, J., Butters, T. D., Michalski, J. C., Matthijs, G., Foulquier, F.
    Quality control of glycoproteins bearing truncated glycans in an ALG9-defective (CDG-IL) patient.
    Glycobiology 19: 910-917 (2009). [PMID: 19451548]
  2. Cipollo, J. F., Trimble, R. B.
    The accumulation of Man6GlcNAc2-PP-dolichol in the Saccharomyces cerevisiae Δalg9 mutant reveals a regulatory role for the Alg3p α1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing.
    J. Biol. Chem. 275: 4267-4277 (2000). [PMID: 10660594]
  3. Frank, C. G., Aebi, M.
    ALG9 mannosyltransferase is involved in two different steps of lipid-linked oligosaccharide biosynthesis.
    Glycobiology 15: 1156-1163 (2005). [PMID: 15987956]

[EC created 1976 as EC, part-transferred 2011 to EC, modified 2012]