EC - Aldos-2-ulose dehydratase

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IntEnz Enzyme Nomenclature


Accepted name:
aldos-2-ulose dehydratase
Other names:
pyranosone dehydratase
1,5-anhydro-D-fructose dehydratase (microthecin-forming)
Systematic name:
1,5-anhydro-D-fructose hydro-lyase (microthecin-forming)



This enzyme catalyses two of the steps in the anhydrofructose pathway, which leads to the degradation of glycogen and starch via 1,5-anhydro-D-fructose [1,2]. Aldose-2-uloses such as 2-dehydroglucose can also act as substrates, but more slowly [1,2,4]. This is a bifunctional enzyme that acts as both a lyase and as an isomerase [2]. Differs from EC, which can carry out only reaction (1a), is inhibited by its product and requires metal ions for activity [1].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0033991


  1. Yu, S. and Fiskesund, R.
    The anhydrofructose pathway and its possible role in stress response and signaling.
    Biochim. Biophys. Acta 1760 : 1314-1322 (2006). [PMID: 16822618]
  2. Yu, S.
    Enzymatic description of the anhydrofructose pathway of glycogen degradation II. Gene identification and characterization of the reactions catalyzed by aldos-2-ulose dehydratase that converts 1,5-anhydro-D-fructose to microthecin with ascopyrone M as the intermediate.
    Biochim. Biophys. Acta 1723 : 63-73 (2005). [PMID: 15716041]
  3. Broberg, A., Kenne, L. and Pedersen, M.
    Presence of microthecin in the red alga Gracilariopsis lemaneiformis and its formation from 1,5-anhydro-D-fructose.
    Phytochemistry 41 : 151-154 (1996).
  4. Gabriel, J., Volc, J., Sedmera, P., Daniel, G. and Kubátová, E.
    Pyranosone dehydratase from the basidiomycete Phanerochaete chrysosporium: improved purification, and identification of 6-deoxy-D-glucosone and D-xylosone reaction products.
    Arch. Microbiol. 160 : 27-34 (1993). [PMID: 8352649]
  5. Yu, S., Refdahl, C. and Lundt, I.
    Enzymatic description of the anhydrofructose pathway of glycogen degradation. I. Identification and purification of anhydrofructose dehydratase, ascopyrone tautomerase and α-1,4-glucan lyase in the fungus Anthracobia melaloma.
    Biochim. Biophys. Acta 1672 : 120-129 (2004). [PMID: 15110094]

[EC created 2006]