EC - Initiation-specific α-1,6-mannosyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
initiation-specific α-1,6-mannosyltransferase
Other names:
GDP-mannose:glycolipid 1,6-α-D-mannosyltransferase
glycolipid 6-α-mannosyltransferase
GDP-mannose:oligosaccharide 1,6-α-D-mannosyltransferase
Systematic name:
GDP-mannose:oligosaccharide 6-α-D-mannosyltransferase




Requires Mn2+. In Saccharomyces cerevisiae, this enzyme catalyses an essential step in the outer chain elongation of N-linked oligosaccharides. Man8GlcNAc and Man9GlcNAc are equally good substrates.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0000009 , GO:0033164
CAS Registry Number: 346003-17-6


  1. Romero, P.A. and Herscovics, A.
    Glycoprotein biosynthesis in Saccharomyces cerevisiae. Characterization of α-1,6-mannosyltransferase which initiates outer chain formation.
    J. Biol. Chem. 264: 1946-1950 (1989). [PMID: 2644248]
  2. Reason, A.J., Dell, A., Romero, P.A. and Herscovics, A.
    Specificity of the mannosyltransferase which initiates outer chain formation in Saccharomyces cerevisiae.
    Glycobiology 1: 387-391 (1992). [PMID: 1820199]
  3. Nakanishi-Shindo, Y., Nakayama, K., Tanaka, A., Toda, Y. and Jigami, Y.
    Structure of the N-linked oligosaccharides that show the complete loss of α-1,6-polymannose outer chain from och1, och1 mnn1, and och1 mnn1 alg3 mutants of Saccharomyces cerevisiae.
    J. Biol. Chem. 268: 26338-26345 (1994). [PMID: 8253757]
  4. Yamamoto, K., Okamoto, M., Yoko-o, T. and Jigami, Y.
    Salt stress induces the expression of Schizosaccharomyces pombe och1+, which encodes an initiation-specific α-1,6-mannosyltransferase for N-linked outer chain synthesis of cell wall mannoproteins.
    Biosci. Biotechnol. Biochem. 67: 927-929 (2003). [PMID: 12784644]
  5. Cui, Z., Horecka, J. and Jigami, Y.
    Cdc4 is involved in the transcriptional control of OCH1, a gene encoding α-1,6-mannosyltransferase in Saccharomyces cerevisiae.
    Yeast 19: 69-77 (2001). [PMID: 11754484]
  6. Tsukahara, K., Watanabe, T., Yoko-o, T. and Chigami, Y.
    Schizosaccharomyces pombe och1+ gene encoding α-1,6-mannosyltransferase and use of och1+ gene knockout fission yeast for production of glycoproteins with reduced glycosylation.
    Jpn. Kokai Tokkyo Koho (2001).
  7. Nakayama, K., Nakanishi-Shindo, Y., Tanaka, A., Haga-Toda, Y. and Jigami, Y.
    Substrate specificity of α-1,6-mannosyltransferase that initiates N-linked mannose outer chain elongation in Saccharomyces cerevisiae.
    FEBS Lett. 412: 547-550 (1997). [PMID: 9276464]
  8. Suzuki, A., Shibata, N., Suzuki, M., Saitoh, F., Takata, Y., Oshie, A., Oyamada, H., Kobayashi, H., Suzuki, S. and Okawa, Y.
    Characterization of α-1,6-mannosyltransferase responsible for the synthesis of branched side chains in Candida albicans mannan.
    Eur. J. Biochem. 240: 37-44 (1996). [PMID: 8797833]
  9. Yip, C.L., Welch, S.K., Klebl, F., Gilbert, T., Seidel, P., Grant, F.J., O'Hara, P.J. and MacKay, V.L.
    Cloning and analysis of the Saccharomyces cerevisiae MNN9 and MNN1 genes required for complex glycosylation of secreted proteins.
    Proc. Natl. Acad. Sci. USA 91: 2723-2727 (1994). [PMID: 8146181]

[EC created 2004]