IUBMB Enzyme Nomenclature


Accepted name: N-acetylneuraminate epimerase

Reaction: N-acetyl-α-neuraminate = N-acetyl-β-neuraminate (oveall reaction)
(1a) N-acetyl-α-neuraminate = aceneuramate
(1b) aceneuramate = N-acetyl-β-neuraminate

Glossary: aceneuramate = (4S,5R,6R,7S,8R)-5-acetamido-4,6,7,8,9-pentahydroxy-2-oxononanoate

Other name(s): sialic acid epimerase; N-acetylneuraminate mutarotase; NanM; NanQ

Systematic name: N-acetyl-α-neuraminate 2-epimerase

Comments: Sialoglycoconjugates present in vertebrates are linked exclusively by α-linkages and are released in α form during degradation. This enzyme accelerates maturotation to the β form via the open form (which also occurs as a slow spontaneous reaction). The open form is necessary for further metabolism by the bacteria.

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


1. Severi, E., Müller, A., Potts, J.R., Leech, A., Williamson, D., Wilson, K.S. and Thomas, G.H. Sialic acid mutarotation is catalyzed by the Escherichia coli β-propeller protein YjhT. J. Biol. Chem. 283 (2008) 4841-4849. [PMID: 18063573]

2. Kentache, T., Thabault, L., Deumer, G., Haufroid, V., Frederick, R., Linster, C.L., Peracchi, A., Veiga-da-Cunha, M., Bommer, G.T. and Van Schaftingen, E. The metalloprotein YhcH is an anomerase providing N-acetylneuraminate aldolase with the open form of its substrate. J. Biol. Chem. (2021) 100699. [PMID: 33895133]

[EC created 2011, modified 2021]

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