IUBMB Enzyme Nomenclature


Accepted name: UDP-N,N'-diacetylbacillosamine 2-epimerase (hydrolysing)

Reaction: UDP-N,N'-diacetylbacillosamine + H2O = UDP + 2,4-diacetamido-2,4,6-trideoxy-D-mannopyranose

For diagram of reaction click here and mechanism click here.

Glossary: UDP-N,N'-diacetylbacillosamine = UDP-2,4-diacetamido-2,4,6-trideoxy-α-D-glucopyranose

Other name(s): UDP-Bac2Ac4Ac 2-epimerase; NeuC

Systematic name: UDP-N,N'-diacetylbacillosamine hydrolase (2-epimerising)

Comments: Requires Mg2+. Involved in biosynthesis of legionaminic acid, a nonulosonate derivative that is incorporated by some bacteria into assorted virulence-associated cell surface glycoconjugates. The initial product formed by the enzyme from Legionella pneumophila, which incorporates legionaminic acid into the O-antigen moiety of its lipopolysaccharide, is 2,4-diacetamido-2,4,6-trideoxy-α-D-mannopyranose, which rapidly mutarotates to a mixture of anomers [1]. The enzyme from Campylobacter jejuni, which incorporates legionaminic acid into flagellin, prefers GDP-N,N'-diacetylbacillosamine [2].

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


1. Glaze, P.A., Watson, D.C., Young, N.M. and Tanner, M.E. Biosynthesis of CMP-N,N'-diacetyllegionaminic acid from UDP-N,N'-diacetylbacillosamine in Legionella pneumophila. Biochemistry 47 (2008) 3272-3282. [PMID: 18275154]

2. Schoenhofen, I.C., Vinogradov, E., Whitfield, D.M., Brisson, J.R. and Logan, S.M. The CMP-legionaminic acid pathway in Campylobacter: biosynthesis involving novel GDP-linked precursors. Glycobiology 19 (2009) 715-725. [PMID: 19282391]

[EC created 2012]

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