Information on EC 4.2.1.123 - tetrahymanol synthase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
4.2.1.123
-
RECOMMENDED NAME
GeneOntology No.
tetrahymanol synthase
-
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
tetrahymanol = squalene + H2O
show the reaction diagram
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Biosynthesis of secondary metabolites
-
-
hopanoid biosynthesis (bacteria)
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-
Sesquiterpenoid and triterpenoid biosynthesis
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-
SYSTEMATIC NAME
IUBMB Comments
squalene-tetrahymanol cyclase
The reaction occurs in the reverse direction.
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
no activity in Alicyclobacillus acidocaldarius
-
-
-
Manually annotated by BRENDA team
no activity in Bradyrhizobium japonicum
-
-
-
Manually annotated by BRENDA team
no activity in Methylococcus capsulatus
-
-
-
Manually annotated by BRENDA team
no activity in Rhodopseudomonas palustris
-
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
metabolism
-
the enzyme converts squalene to tetrahymanol, EC 4.2.1.123, and to hopanol, EC 4.2.1.129, pathway overview
additional information
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
dihydrosqualene + H2O
euph-7-ene
show the reaction diagram
-
-
-
-
?
squalene + H2O
tetrahymanol
show the reaction diagram
squalene + H2O
tetrahymanol + diplopterol
show the reaction diagram
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
squalene + H2O
tetrahymanol
show the reaction diagram
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2,3-Iminosqualene
-
effective inhibitor, complete inhibition at 1 mM
4,4,10beta-trimethyltransdecal-3beta-ol
-
25% inhibition at 40 mM
4-chloromercuribenzenesulfonic acid
-
86% inhibition at 5 mM
diethyldicarbonate
-
complete inhibition at 5 mM
Digitonin
-
solubilization of the cyclase in 8 mg/ml digitonin inactivates the enzyme, its activity can be recovered by complementation of the assay buffer with octylthioglucoside above its critical micellar concentration
Emulgene 911
-
solubilization of the cyclase in 1 mg/ml Emulgene 911 inactivates the enzyme
N,N-Dimethyldodecylamine-N-oxide
-
effective inhibitor, complete inhibition at 1 mM
Ro 43-8522
-
effective inhibitor, complete inhibition at 1 mM
Triton X-100
-
strong inactivator
Tween 80
-
solubilization of the cyclase in 30 mg/ml Tween 80 inactivates the enzyme, its activity can be recovered by complementation of the assay buffer with octylthioglucoside above its critical micellar concentration
additional information
-
the cyclase is not influenced by EDTA concentrations up to 0.1 M, and lodoacetate is not inhibitory at 1 and 5 mM
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.018
squalene
-
pH 7.0, 30°C
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00003
2,3-Iminosqualene
Tetrahymena thermophila
-
pH 7.0, 30°C
0.00005
N,N-Dimethyldodecylamine-N-oxide
Tetrahymena thermophila
-
pH 7.0, 30°C
0.00004
Ro 43-8522
Tetrahymena thermophila
-
pH 7.0, 30°C
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
105
-
enzyme from homogenate, pH 7.0, 30°C
31280
-
enzyme after 297fold purification, pH 7.0, 30°C
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
-
x * 72000, SDS-PAGE
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4 - 8.5
-
the enzyme is not active beyond the pH limits of pH 4.5 and 8.0
714282
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
50
-
the enzyme is not active at 50°C
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-80°C, whole cells and particulate material, 6 months, no loss of activity
-
6°C, octylthioglucoside-solubilized enzyme, one week, almost complete loss of activity
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
DEAE-trisacryl column chromatography, hydroxyapatite column chromatography, and Mono Q column chromatography
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
phylogenetic analysis