4.2.1.110	1,5-anhydro-D-fructose	-	Phanerodontia chrysosporium	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	microthecin + H2O	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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]. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Sarcodontia unicolor	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Gracilariopsis lemaneiformis	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Morchella costata	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Morchella vulgaris	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Phanerodontia chrysosporium	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Microthecium compressum	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Microthecium sobelii	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	?	383008	
4.2.1.110	1,5-anhydro-D-fructose	formation of microthecin is irreversible. 1,5-anhydro-D-fructose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O (overall reaction), (1a) 1,5-anhydro-D-fructose = 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose + H2O, (1b) 1,5-anhydro-4-deoxy-D-glycero-hex-3-en-2-ulose = 2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one. 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. The other enzymes involved in this pathway are EC 4.2.1.111 (1,5-anhydro-D-fructose dehydratase), EC 4.2.2.13 (exo-(1,4)-alpha-D-glucan lyase) and EC 5.3.3.15 (ascopyrone tautomerase). This is a bifunctional enzyme that acts as both a lyase and as an isomerase. Differs from EC 4.2.1.111, which can carry out only reaction 1a	Phanerodontia chrysosporium	2-hydroxy-2-(hydroxymethyl)-2H-pyran-3(6H)-one + H2O	i.e. microthecin	ir	383008	
4.2.1.110	1,5-D-anhydrofructose	dehydration reaction most likely follows an elimination mechanism, where Zn2+ acts as a Lewis acid polarizing the C2 oxo group of 1,5-D-anhydrofructose. The reaction intermediate ascopyrone M shows binding of this compound at two different sites, with direct coordination to Zn2+ in the propeller domain and as second sphere ligand of the metal ion in the cupin domain	Phanerodontia chrysosporium	microthecin	-	?	429580	
4.2.1.110	D-glucosone	i.e. D-arabino-hexos-2-ulose. The enzyme dehydrates D-arabino-hexos-2-ulose, generating a double bond between C-3 and C-4. This unsaturated compound is proposed to be the steady-state intermediate characterized by the spectral peak at 265 nm. This intermediate is chemically unstable and rearranges from its strained 1,5 ring form to a more stable 2,6 pyranose structure. Then the enzyme acts a second time, dehydrating this pyranose structure to form cortalcerone	Polyporus obtusus	cortalcerone + H2O	i.e. 5,6-dihydro-6-hydroxy-5-oxo-2H-pyran-6-carboxaldehyde	?	420543	
4.2.1.110	D-glucosone	i.e. D-arabino-hexos-2-ulose. The enzyme dehydrates D-arabino-hexos-2-ulose, generating a double bond between C-3 and C-4. This unsaturated compound is proposed to be the steady-state intermediate characterized by the spectral peak at 265 nm. This intermediate is chemically unstable and rearranges from its strained 1,5 ring form to a more stable 2,6 pyranose structure. Then the enzyme acts a second time, dehydrating this pyranose structure to form cortalcerone	Polyporus obtusus AU124PD	cortalcerone + H2O	i.e. 5,6-dihydro-6-hydroxy-5-oxo-2H-pyran-6-carboxaldehyde	?	420543	
4.2.1.110	D-xylosone	i.e. D-threo-pentos-2-ulose	Polyporus obtusus	?	the product absorbs at 260 nm but no conversion into a 230 nm-absorbing product occurs. Because of its strained nature, the intermediate still rearranges, losing UV absorbance, but since it lacks the 6th carbon, it cannot form a 2,6-pyranose ring to generate a second substrate for the enzyme	?	420557	
4.2.1.110	D-xylosone	i.e. D-threo-pentos-2-ulose	Polyporus obtusus AU124PD	?	the product absorbs at 260 nm but no conversion into a 230 nm-absorbing product occurs. Because of its strained nature, the intermediate still rearranges, losing UV absorbance, but since it lacks the 6th carbon, it cannot form a 2,6-pyranose ring to generate a second substrate for the enzyme	?	420557	
4.2.1.110	glucosone	-	Phanerodontia chrysosporium	cortalcerone + H2O	-	?	384788	
4.2.1.110	glucosone	-	Sarcodontia unicolor	cortalcerone + H2O	-	?	384788	
4.2.1.110	glucosone	20% of the activity with 1,5-anhydro-D-fructose	Phanerodontia chrysosporium	cortalcerone + H2O	-	?	384788	
4.2.1.110	glucosone	2-keto glucose	Phanerodontia chrysosporium	cortalcerone + H2O	-	?	384788	
4.2.1.110	additional information	no activity with fructose	Polyporus obtusus	?	-	?	89	
4.2.1.110	additional information	the enzyme is bifunctional and is also active with glucosone and xylosone, the former is converted to cortalcerone	Phanerodontia chrysosporium	?	-	?	89	
4.2.1.110	additional information	no activity with fructose	Polyporus obtusus AU124PD	?	-	?	89