Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
46  structures 4630  species 0  interactions 8028  sequences 22  architectures

Family: Epimerase_2 (PF02350)

Summary: UDP-N-acetylglucosamine 2-epimerase

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "UDP-N-acetylglucosamine 2-epimerase". More...

UDP-N-acetylglucosamine 2-epimerase Edit Wikipedia article

UDP-N-acetylglucosamine 2-epimerase
EC number5.1.3.14
CAS number9037-71-2
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
UDP-N-acetylglucosamine 2-epimerase
PDB 1vgv EBI.jpg
crystal structure of udp-n-acetylglucosamine_2 epimerase
Pfam clanCL0113

In enzymology, an UDP-N-acetylglucosamine 2-epimerase (EC is an enzyme that catalyzes the chemical reaction

UDP-N-acetyl-D-glucosamine UDP-N-acetyl-D-mannosamine

Hence, this enzyme has one substrate, UDP-N-acetyl-D-glucosamine, and one product, UDP-N-acetyl-D-mannosamine.

This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on carbohydrates and derivatives. The systematic name of this enzyme class is UDP-N-acetyl-D-glucosamine 2-epimerase. Other names in common use include UDP-N-acetylglucosamine 2'-epimerase, uridine diphosphoacetylglucosamine 2'-epimerase, uridine diphospho-N-acetylglucosamine 2'-epimerase, and uridine diphosphate-N-acetylglucosamine-2'-epimerase. This enzyme participates in aminosugars metabolism.

In microorganisms this epimerase is involved in the synthesis of the capsule precursor UDP-ManNAcA.[1][2] An inhibitor of the bacterial 2-epimerase, epimerox, has been described. Some of these enzymes are bifunctional. The UDP-N-acetylglucosamine 2-epimerase from rat liver displays both epimerase and kinase activity.[3]

Structural studies

As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1F6D, 1O6C, 1V4V, and 1VGV.


  1. ^ Swartley JS, Liu LJ, Miller YK, Martin LE, Edupuganti S, Stephens DS (March 1998). "Characterization of the Gene Cassette Required for Biosynthesis of the (α1→6)-Linked N-Acetyl-d-Mannosamine-1-Phosphate Capsule of Serogroup A Neisseria meningitidis". J. Bacteriol. 180 (6): 1533–9. PMC 107054. PMID 9515923.
  2. ^ Kiser KB, Lee JC (January 1998). "Staphylococcus aureus cap5O and cap5P Genes Functionally Complement Mutations Affecting Enterobacterial Common-Antigen Biosynthesis in Escherichia coli". J. Bacteriol. 180 (2): 403–6. PMC 106897. PMID 9440531.
  3. ^ Stasche R, Hinderlich S, Weise C, Effertz K, Lucka L, Moormann P, Reutter W (September 1997). "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 (39): 24319–24. doi:10.1074/jbc.272.39.24319. PMID 9305888.

Further reading

  • Kikuchi K, Tsuiki S (1973). "Purification and properties of UDP-N-acetylglucosamine 2'-epimerase from rat liver". Biochim. Biophys. Acta. 327 (1): 193–206. doi:10.1016/0005-2744(73)90117-4. PMID 4770741.
This article incorporates text from the public domain Pfam and InterPro: IPR003331

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

UDP-N-acetylglucosamine 2-epimerase Provide feedback

This family consists of UDP-N-acetylglucosamine 2-epimerases EC: this enzyme catalyses the production of UDP-ManNAc from UDP-GlcNAc. Note that some of the enzymes is this family are bifunctional such as O35826 and Q9Z0P6 in this instance Pfam matches only the N-terminal half of the protein suggesting that the additional C-terminal part (when compared to mono-functional members of this family) is responsible for the UPD-N-acetylmannosamine kinase activity of these enzymes. This hypothesis is further supported by the assumption that the C-terminal part of O35826 is the kinase domain [3].

Literature references

  1. Swartley JS, Liu LJ, Miller YK, Martin LE, Edupuganti S, Stephens DS; , J Bacteriol. 1998;180:1533-1539.: Characterization of the gene cassette required for biosynthesis of the (alpha1-->6)-linked N-acetyl-D-mannosamine-1-phosphate capsule of serogroup A Neisseria meningitidis. PUBMED:9515923 EPMC:9515923

  2. Kiser KB, Lee JC; , J Bacteriol 1998;180:403-406.: Staphylococcus aureus cap5O and cap5P genes functionally complement mutations affecting enterobacterial common-antigen biosynthesis in Escherichia coli. PUBMED:9440531 EPMC:9440531

  3. Stasche R, Hinderlich S, Weise C, Effertz K, Lucka L, Moormann P, Reutter W; , J Biol Chem 1997;272:24319-24324.: 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. PUBMED:9305888 EPMC:9305888

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR003331

This entry represents a domain found in the bacterial UDP-N-acetylglucosamine 2-epimerase WecB, which is involved in the enterobacterial common antigen biosynthesis [ PUBMED:2166030 ]. It can also be found in the N-terminal region of the mammalian bifunctional protein GNE, which has both the UDP-N-acetylglucosamine 2-epimerase and the N-acetylmannosamine kinase functions. GNE catalyses the first two steps of sialic acid biosynthesis in the cytosol [ PUBMED:11929971 ].

Proteins containing this domain also include UDP-N,N'-diacetylbacillosamine 2-epimerase, which is involved in biosynthesis of legionaminic acid (5,7-diamino-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid)(Leg), a sialic acid-like derivative that is incorporated into virulence-associated cell surface glycoconjugates such as lipopolysaccharide (LPS) which could be a key determinant in the ability of L. pneumophila to inhibit the fusion of phagosomes with lysosomes [ PUBMED:18275154 ].

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

Loading domain graphics...


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes UniProt
Jalview View  View  View  View  View  View  View 
HTML View             
PP/heatmap 1            

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

Representative proteomes UniProt

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

Representative proteomes UniProt
Raw Stockholm Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_888 (release 5.2) & Pfam-B_4862 (Release 7.5)
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: Bashton M , Bateman A
Number in seed: 82
Number in full: 8028
Average length of the domain: 330.60 aa
Average identity of full alignment: 29 %
Average coverage of the sequence by the domain: 83.07 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 30.6 30.6
Trusted cut-off 30.6 30.6
Noise cut-off 30.5 30.5
Model length: 346
Family (HMM) version: 22
Download: download the raw HMM for this family

Species distribution

Sunburst controls


Weight segments by...

Change the size of the sunburst


Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls


The tree shows the occurrence of this domain across different species. More...


Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Epimerase_2 domain has been found. There are 46 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

Loading structure mapping...