EC - UDP-N-acetylglucosamine 2-epimerase (hydrolysing)

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IntEnz Enzyme Nomenclature


Accepted name:
UDP-N-acetylglucosamine 2-epimerase (hydrolysing)
Other names:
UDP-N-acetylglucosamine 2-epimerase [ambiguous]
GNE (gene name)
siaA (gene name)
neuC (gene name)
Systematic name:
UDP-N-acetyl-α-D-glucosamine hydrolase (2-epimerising)



The enzyme is found in mammalian liver, as well as in some pathogenic bacteria including Neisseria meningitidis and Staphylococcus aureus. It catalyses the first step of sialic acid (N-acetylneuraminic acid) biosynthesis. The initial product formed is the α anomer, which rapidly mutarotates to a mixture of anomers [2]. The mammalian enzyme is bifunctional and also catalyses EC, N-acetylmannosamine kinase. cf. EC, UDP-N-acetylglucosamine 2-epimerase (non-hydrolysing).

Links to other databases

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


  1. Stasche, R., Hinderlich, S., Weise, C., Effertz, K., Lucka, L., Moormann, P., Reutter, W.
    A bifunctional enzyme catalyzes the first two steps in N-acetylneuraminic acid biosynthesis of rat liver. Molecular cloning and functional expression of UDP-N-acetyl-glucosamine 2-epimerase/N-acetylmannosamine kinase.
    J. Biol. Chem. 272: 24319-24324 (1997). [PMID: 9305888]
  2. Chou, W. K., Hinderlich, S., Reutter, W., Tanner, M. E.
    Sialic acid biosynthesis: stereochemistry and mechanism of the reaction catalyzed by the mammalian UDP-N-acetylglucosamine 2-epimerase.
    J. Am. Chem. Soc. 125: 2455-2461 (2003). [PMID: 12603133]
  3. Blume, A., Ghaderi, D., Liebich, V., Hinderlich, S., Donner, P., Reutter, W., Lucka, L.
    UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, functionally expressed in and purified from Escherichia coli, yeast, and insect cells.
    Protein Expr. Purif. 35: 387-396 (2004). [PMID: 15135418]
  4. Murkin, A. S., Chou, W. K., Wakarchuk, W. W., Tanner, M. E.
    Identification and mechanism of a bacterial hydrolyzing UDP-N-acetylglucosamine 2-epimerase.
    Biochemistry 43: 14290-14298 (2004). [PMID: 15518580]

[EC created 2012]