IUBMB Enzyme Nomenclature


Accepted name: GDP-Man:Man2GlcNAc2-PP-dolichol α-1,6-mannosyltransferase

Reaction: GDP-D-mannose + D-Man-α-(1→3)-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol = GDP + D-Man-α-(1→3)-[D-Man-α-(1→6)]-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol

For diagram of reaction click here.

Other name(s): GDP-Man:Man2GlcNAc2-PP-Dol α-1,6-mannosyltransferase; Alg2 mannosyltransferase (ambiguous); ALG2 (gene name, ambiguous); GDP-Man:Man1GlcNAc2-PP-dolichol mannosyltransferase (ambiguous)

Systematic name: GDP-D-mannose:D-Man-α-(1→3)-D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-D-GlcNAc-diphosphodolichol α-6-mannosyltransferase

Comments: The biosynthesis of asparagine-linked glycoproteins utilizes a dolichyl diphosphate-linked glycosyl donor, which is assembled by the series of membrane-bound glycosyltransferases that comprise the dolichol pathway. Alg2 mannosyltransferase from Saccharomyces cerevisiae carries out an α1,3-mannosylation (cf. EC of D-Man-β-(1→4)-D-GlcNAc-β-(1→4)-GlcNAc-diphosphodolichol, followed by an α1,6-mannosylation, to form the first branched pentasaccharide intermediate of the dolichol pathway [1,2].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Kampf, M., Absmanner, B., Schwarz, M. and Lehle, L. Biochemical characterization and membrane topology of Alg2 from Saccharomyces cerevisiae as a bifunctional α1,3- and 1,6-mannosyltransferase involved in lipid-linked oligosaccharide biosynthesis. J. Biol. Chem. 284 (2009) 11900-11912. [PMID: 19282279]

2. O'Reilly, M.K., Zhang, G. and Imperiali, B. In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45 (2006) 9593-9603. [PMID: 16878994]

[EC created 2011, modified 2012]

Return to EC 2.4.1 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