4.2.1.143: versicolorin B synthase
This is an abbreviated version!
For detailed information about versicolorin B synthase, go to the full flat file.
Word Map on EC 4.2.1.143
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4.2.1.143
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aflatoxin
-
aspergillus
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hemiacetal
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parasiticus
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mycotoxin
-
cyclization
-
racemic
-
coumarins
-
flavoenzymes
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polyketide
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adp-binding
- 4.2.1.143
- aflatoxin
- aspergillus
- hemiacetal
- parasiticus
-
mycotoxin
-
cyclization
-
racemic
- coumarins
-
flavoenzymes
- polyketide
-
adp-binding
Reaction
Synonyms
aflK, OAVN cyclase, VBS, versicolorin B synthase
ECTree
4.2.1.143 versicolorin B synthaseAdvanced search results
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results (Substrates Products
Substrates Products on EC 4.2.1.143 - versicolorin B synthase
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SUBSTRATE 
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
versiconal
(-)-versicolorin B + H2O
-
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione
-
?
versiconal
(-)-versicolorin B + H2O
-
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione
-
?
versiconal
versicolorin B + H2O
Aspergillus flavus ATCC 200026 / FGSC A1120 / NRRL 3357 / JCM 12722 / SRRC 167
-
-
-
?
versiconal
versicolorin B + H2O
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione
-
?
versiconal
versicolorin B + H2O
-
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione
-
?
versiconal
versicolorin B + H2O
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione
-
?
versiconal hemiacetal
versicolorin B + H2O
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione,
-
?
versiconal hemiacetal
versicolorin B + H2O
i.e. (2S,3S)-2,4,6,8-tetrahydroxy-3-(2-hydroxyethyl)anthra[2,3-b]furan-5,10-dione
(3aR,12bS)-8,10,12-trihydroxy-1,2,3a,12b-tetrahydroanthra[2,3-b]furo[3,2-d]furan-6,11-dione,
-
?
additional information
?
-
enzyme selects from two equilibrating enantiomers of versiconal hemiacetal to cyclize the appropriate antipode to optically pure versicolorin B. By varying the amount of enzyme to a fixed concentration of substrate, the rate of enzymic cyclization can be limited by the intrinsic rate of enantiomerization of the substrate under the conditions of reaction
-
-
?
additional information
?
-
-
enzyme selects from two equilibrating enantiomers of versiconal hemiacetal to cyclize the appropriate antipode to optically pure versicolorin B. By varying the amount of enzyme to a fixed concentration of substrate, the rate of enzymic cyclization can be limited by the intrinsic rate of enantiomerization of the substrate under the conditions of reaction
-
-
?
additional information
?
-
in addition, enzyme catalyzes the conversion of 5'-oxoaverantin to (2'S,5'S)-averufin, reaction of EC 4.2.1.142, 5'-oxoaverantin cyclase
-
-
?
additional information
?
-
-
racemic versiconal hemiacetate or racemic versiconal leads exclusively to formation of (1'R,2'S)-(-)-versicolorin B. Only (1'R,2'S)-(-)-versicolorin B, and not (1'S,2'R)-(+)antipode, serves as a substrate for desaturase activity in the following reaction of the aflatoxin biosynthetic pathway. Thus the stereoconfiguration of bis-furan moiety in aflatoxin molecules is determined by the cyclase enzyme catalyzing the reaction from versiconal to versicolorinB. Nonenzymatic racemization in both the (2'R)- and (2'S)-versiconal hemiacetate enantiomers is dependent upon the temperature and alkaline conditions
-
-
?
additional information
?
-
enzyme selects from two equilibrating enantiomers of versiconal hemiacetal to cyclize the appropriate antipode to optically pure versicolorin B. By varying the amount of enzyme to a fixed concentration of substrate, the rate of enzymic cyclization can be limited by the intrinsic rate of enantiomerization of the substrate under the conditions of reaction
-
-
?
additional information
?
-
-
racemic versiconal hemiacetate or racemic versiconal leads exclusively to formation of (1'R,2'S)-(-)-versicolorin B. Only (1'R,2'S)-(-)-versicolorin B, and not (1'S,2'R)-(+)antipode, serves as a substrate for desaturase activity in the following reaction of the aflatoxin biosynthetic pathway. Thus the stereoconfiguration of bis-furan moiety in aflatoxin molecules is determined by the cyclase enzyme catalyzing the reaction from versiconal to versicolorinB. Nonenzymatic racemization in both the (2'R)- and (2'S)-versiconal hemiacetate enantiomers is dependent upon the temperature and alkaline conditions
-
-
?
additional information
?
-
in addition, enzyme catalyzes the conversion of 5'-oxoaverantin to (2'S,5'S)-averufin, reaction of EC 4.2.1.142, 5'-oxoaverantin cyclase
-
-
?
