EC - Mannosyl-oligosaccharide 1,3-1,6-α-mannosidase

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IntEnz Enzyme Nomenclature


Accepted name:
mannosyl-oligosaccharide 1,3-1,6-α-mannosidase
Other names:
α-D-mannosidase II
α-mannosidase II
GlcNAc transferase I-dependent α1,3[α1,6]mannosidase
Golgi α-mannosidase II
mannosidase II
1,3-(1,6-)mannosyl-oligosaccharide α-D-mannohydrolase
(1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase
Systematic name:
(1→3)-(1→6)-mannosyl-oligosaccharide α-D-mannohydrolase (configuration-retaining)



The enzyme, found in plants and animals, participates in the processing of N-glycans in the Golgi apparatus. It removes two mannosyl residues, one linked by α1,3 linkage, and the other linked by α1,6 linkage, both of which are removed by the same catalytic site. The enzyme is sensitive to swainsonine.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004572


  1. Tulsiani, D.R.P., Opheim, D.J. and Touster, O.
    Purification and characterization of α-D-mannosidase from rat liver Golgi membranes.
    J. Biol. Chem. 252: 3227-3233 (1977). [PMID: 863880]
  2. Tabas, I., Kornfeld, S.
    The synthesis of complex-type oligosaccharides. III. Identification of an α-D-mannosidase activity involved in a late stage of processing of complex-type oligosaccharides.
    J. Biol. Chem. 253: 7779-7786 (1978). [PMID: 212436]
  3. Harpaz, N., Schachter, H.
    Control of glycoprotein synthesis. Processing of asparagine-linked oligosaccharides by one or more rat liver Golgi α-D-mannosidases dependent on the prior action of UDP-N-acetylglucosamine: α-D-mannoside β 2-N-acetylglucosaminyltransferase I.
    J. Biol. Chem. 255: 4894-4902 (1980). [PMID: 6445359]
  4. Tulsiani, D.R.P., Hubbard, S.C., Robbins, P.W. and Touster, O.
    α-D-Mannosidases of rat liver Golgi membranes. Mannosidase II is the GlcNAcMAN5-cleaving enzyme in glycoprotein biosynthesis and mannosidases Ia and IB are the enzymes converting Man9 precursors to Man5 intermediates.
    J. Biol. Chem. 257: 3660-3668 (1982). [PMID: 7061502]
  5. Moremen, K. W., Robbins, P. W.
    Isolation, characterization, and expression of cDNAs encoding murine alpha-mannosidase II, a Golgi enzyme that controls conversion of high mannose to complex N-glycans.
    J. Cell Biol. 115: 1521-1534 (1991). [PMID: 1757461]
  6. Misago, M., Liao, Y. F., Kudo, S., Eto, S., Mattei, M. G., Moremen, K. W., Fukuda, M. N.
    Molecular cloning and expression of cDNAs encoding human alpha-mannosidase II and a previously unrecognized alpha-mannosidase IIx isozyme.
    Proc. Natl. Acad. Sci. U.S.A. 92: 11766-11770 (1995). [PMID: 8524845]
  7. van den Elsen, J. M., Kuntz, D. A., Rose, D. R.
    Structure of Golgi alpha-mannosidase II: a target for inhibition of growth and metastasis of cancer cells.
    EMBO J. 20: 3008-3017 (2001). [PMID: 11406577]
  8. Athanasopoulos, V. I., Niranjan, K., Rastall, R. A.
    The production, purification and characterisation of two novel α-D-mannosidases from Aspergillus phoenicis.
    Carbohydr. Res. 340: 609-617 (2005). [PMID: 15721331]
  9. Shah, N., Kuntz, D. A., Rose, D. R.
    Golgi alpha-mannosidase II cleaves two sugars sequentially in the same catalytic site.
    Proc. Natl. Acad. Sci. U.S.A. 105: 9570-9575 (2008). [PMID: 18599462]
  10. Rose, D. R.
    Structure, mechanism and inhibition of Golgi ?-mannosidase II.
    Curr. Opin. Struct. Biol. 22: 558-562 (2012). [PMID: 22819743]

[EC created 1986]