KEGG   ENZYME: 4.2.1.110Help
Entry
EC 4.2.1.110                Enzyme                                 

Name
aldos-2-ulose dehydratase;
pyranosone dehydratase;
AUDH;
1,5-anhydro-D-fructose dehydratase (microthecin-forming)
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
BRITE hierarchy
Sysname
1,5-anhydro-D-fructose hydro-lyase (microthecin-forming)
Reaction(IUBMB)
1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-on + H2O (overall reaction) [RN:R09696];
(1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O [RN:R09694];
(1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one [RN:R09695]
Reaction(KEGG)
Substrate
1,5-anhydro-D-fructose [CPD:C06485];
1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose [CPD:C19822]
Product
2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-on;
H2O [CPD:C00001];
1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose [CPD:C19822];
2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one [CPD:C19821]
Comment
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 4.2.1.111, which can carry out only reaction (1a), is inhibited by its product and requires metal ions for activity [1].
History
EC 4.2.1.110 created 2006
Reference
1  [PMID:16822618]
  Authors
Yu S, Fiskesund R.
  Title
The anhydrofructose pathway and its possible role in stress response and signaling.
  Journal
Biochim. Biophys. Acta. 1760 (2006) 1314-22.
Reference
2  [PMID:15716041]
  Authors
Yu S.
  Title
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.
  Journal
Biochim. Biophys. Acta. 1723 (2005) 63-73.
Reference
3
  Authors
Broberg, A., Kenne, L. and Pedersen, M.
  Title
Presence of microthecin in the red alga Gracilariopsis lemaneiformis and its formation from 1,5-anhydro-D-fructose.
  Journal
Phytochemistry 41 (1996) 151-154.
Reference
4  [PMID:8352649]
  Authors
Gabriel J, Volc J, Sedmera P, Daniel G, Kubatova E.
  Title
Pyranosone dehydratase from the basidiomycete Phanerochaete chrysosporium: improved purification, and identification of 6-deoxy-D-glucosone and D-xylosone reaction products.
  Journal
Arch. Microbiol. 160 (1993) 27-34.
Reference
5  [PMID:15110094]
  Authors
Yu S, Refdahl C, Lundt I.
  Title
Enzymatic description of the anhydrofructose pathway of glycogen degradation; I. Identification and purification of anhydrofructose dehydratase, ascopyrone tautomerase and alpha-1,4-glucan lyase in the fungus Anthracobia melaloma.
  Journal
Biochim. Biophys. Acta. 1672 (2004) 120-9.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
UM-BBD (Biocatalysis/Biodegradation Database): 
BRENDA, the Enzyme Database: 
CAS: 
101920-80-3

DBGET integrated database retrieval system