IUBMB Enzyme Nomenclature


Accepted name: initiation-specific α-1,6-mannosyltransferase

Reaction: Transfers an α-D-mannosyl residue from GDP-mannose into lipid-linked oligosaccharide, forming an α-(1→6)-D-mannosyl-D-mannose linkage

Other name(s): α-1,6-mannosyltransferase; GDP-mannose:oligosaccharide 1,6-α-D-mannosyltransferase; GDP-mannose:glycolipid 1,6-α-D-mannosyltransferase; glycolipid 6-α-mannosyltransferase

Systematic name: GDP-mannose:oligosaccharide 1,6-α-D-mannosyltransferase

Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, 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 (1989) 1946-1950. [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 (1991) 387-391. [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 (1993) 26338-26345. [PMID: 8253757]

4. Yamamoto, K., Okamoto, M., Yoko-o, T. and Jigami, Y. Salt stress induces the expression of the 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 (2003) 927-929. [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 (2002) 69-77. [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) 11 pp.

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 (1997) 547-550. [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 (1996) 37-44. [PMID: 8797833]

9. Yip, C.L., Welch, S.K., Klebl, F., Gilbert, T., Seidel, P., Grant, F., 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 (1994) 2723-2727. [PMID: 8146181]

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