BRENDA home
History
Enzyme Nomenclature
Information on EC 4.2.1.123 - tetrahymanol synthase
for references in articles please use BRENDA:EC4.2.1.123Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
EC Tree
4.2.1.123 tetrahymanol synthaseIUBMB Comments
The reaction occurs in the reverse direction.
Specify your search results
Word Map
- 4.2.1.123
- sterol
-
tetrahymena
-
triterpenoids
-
cyclization
-
oxygen-poor
-
squalene-hopene
-
ciliate
- thermophila
-
oxygen-independent
-
sterol-independent
-
sterol-free
-
bacterivore
- pyriformis
- diagnostics
The enzyme appears in viruses and cellular organisms
topPlease wait a moment until the data is sorted. This message will disappear when the data is sorted.
SYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
squalene-tetrahymanol cyclase
STC
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
tetrahymanol = squalene + H2O
-
-
-
-
tetrahymanol = squalene + H2O
overall mechanism of the polycyclization reaction of SHCs and structures of squalene cyclization products, overview
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
PATHWAY SOURCE
PATHWAYS
MetaCyc
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SYSTEMATIC NAME
IUBMB Comments
squalene-tetrahymanol cyclase
The reaction occurs in the reverse direction.
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
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
squalene + H2O
tetrahymanol + diplopterol
-
-
diplopterol amounts to less than 2% of the total products formed by enzymatic conversion
-
?
squalene + H2O
tetrahymanol + diplopterol
-
-
diplopterol amounts to less than 2% of the total products formed by enzymatic conversion
-
?
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
NATURAL SUBSTRATE
NATURAL 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
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
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
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
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
metabolism
-
the enzyme converts squalene to tetrahymanol, EC 4.2.1.123, and to hopanol, EC 4.2.1.129, pathway overview
physiological function
additional information
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
-
genes encoding the tetrahymanol synthesizing enzyme squalene-tetrahymanol cyclase are found from several phylogenetically diverged eukaryotes that live in oxygen-poor environments and appear to have been laterally transferred among such eukaryotes, overview
evolution
phylogenetic evidence reveals that the last common ancestor of diplomonads was dependent on a host and that Trepomonas has adapted secondarily to a free-living lifestyle. Free-living taxa are nested within parasites reveals more examples of secondarily free-living eukaryotes, transcriptome study of Trepomonas sp. PC1, a diplomonad isolated from marine sediment. Phylogenetic analyses show that most of the differences in metabolic capacity between free-living Trepomonas and the parasitic diplomonads are due to recent acquisitions of bacterial genes via gene transfer. The transcriptome includes a gene encoding squalene-tetrahymanol cyclase. This enzyme synthesizes the sterol substitute tetrahymanol in the absence of oxygen, potentially allowing Trepomonas to thrive under anaerobic conditions as a free-living bacterivore, without depending on sterols from other eukaryotes
evolution
the eukaryotic squalene-tetrahymanol cyclase is homologous to the bacterial tetrahymanol synthase (Ths), that is not encoded in any eukaryotic genomes. Bacterial tetrahymanol synthase (Ths) is found in a variety of bacterial genomes, including aerobic methanotrophs, nitrite-oxidizers, and sulfate-reducers, and in a subset of aquatic and terrestrial metagenomes
evolution
-
the eukaryotic squalene-tetrahymanol cyclase is homologous to the bacterial tetrahymanol synthase (Ths), that is not encoded in any eukaryotic genomes. Bacterial tetrahymanol synthase (Ths) is found in a variety of bacterial genomes, including aerobic methanotrophs, nitrite-oxidizers, and sulfate-reducers, and in a subset of aquatic and terrestrial metagenomes
-
physiological function
eukaryotic squalene-tetrahymanol cyclase catalyzes the cyclization of squalene directly to tetrahymanol, a polycyclic triterpenoid lipid, the enzyme catalyzes the cyclization of squalene directly to tetrahymanol
physiological function
the enzyme synthesizes the sterol substitute tetrahymanol in the absence of oxygen, potentially allowing Trepomonas to thrive under anaerobic conditions as a free-living bacterivore, without depending on sterols from other eukaryotes. Several microbial eukaryotes that live under anoxic conditions employ the sterol substitute tetrahymanol, which can be synthesized without molecular oxygen. The Trepomonas transcriptome includes a homologue of STC, the enzyme required to synthesize tetrahymanol
physiological function
-
eukaryotic squalene-tetrahymanol cyclase catalyzes the cyclization of squalene directly to tetrahymanol, a polycyclic triterpenoid lipid, the enzyme catalyzes the cyclization of squalene directly to tetrahymanol
-
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
additional information
-
tetrahymanol, a triterpenoid that does not require molecular oxygen for its biosynthesis, likely functions as a surrogate of sterol in eukaryotes inhabiting oxygen-poor environments
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). Q24FB1_TETTS
Tetrahymena thermophila (strain SB210)
655
0
76021
TrEMBL
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
72000
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
4 - 8.5
-
the enzyme is not active beyond the pH limits of pH 4.5 and 8.0
714282
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
CHAPS
CHAPS
-
CHAPS effectively solubilizes the enzyme and maintains its activity
CHAPS
-
CHAPS effectively solubilizes the enzyme and maintains its activity
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
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
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
DEAE-trisacryl column chromatography, hydroxyapatite column chromatography, and Mono Q column chromatography
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
gene ths, DNA and amino acid sequence determination and analysis, sequence comparisons
gene TPC1_17222, sequence comparisons and phylogenetic analysis, transcriptome analysis
phylogenetic analysis
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
diagnostics
diagnostics
tetrahymanol is a polycyclic triterpenoid lipid in the Tetrahymena ciliates. The diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems
diagnostics
tetrahymanol is a polycyclic triterpenoid lipid in the Tetrahymena ciliates. The diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems
diagnostics
-
tetrahymanol is a polycyclic triterpenoid lipid in the Tetrahymena ciliates. The diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Saar, J.; Kader, J.; Poralla, K.; Ourisson, G.
Purification and some properties of the squalene-tetrahymanol cyclase from Tetrahymena thermophila
Biochim. Biophys. Acta
1075
93-101
1991
Tetrahymena thermophila, Tetrahymena thermophila B4-1868 (ATCC 30382)
brenda
Giner, J.; Rocchetti, S.; Neunlist, S.; Rohmer, M.; Arigoni, D.
Detection of 1,2-hydride shifts in the formation of euph-7-ene by the squalene-tetrahymanol cyclase of Tetrahymena pyriformis
Chem. Commun. (Camb. )
2005
3089-3091
2005
Tetrahymena pyriformis
-
brenda
Siedenburg, G.; Jendrossek, D.
Squalene-hopene cyclases
Appl. Environ. Microbiol.
77
3905-3915
2011
no activity in Alicyclobacillus acidocaldarius, no activity in Bradyrhizobium japonicum, no activity in Methylococcus capsulatus, no activity in Rhodopseudomonas palustris, Tetrahymena thermophila
brenda
Takishita, K.; Chikaraishi, Y.; Leger, M.M.; Kim, E.; Yabuki, A.; Ohkouchi, N.; Roger, A.J.
Lateral transfer of tetrahymanol-synthesizing genes has allowed multiple diverse eukaryote lineages to independently adapt to environments without oxygen
Biol. Direct
7
0000
2012
Alvinella pompejana, Paramecium tetraurelia, Paratrimastix pyriformis, Piromyces sp., Sawyeria marylandensis, Stygiella incarcerata, Tetrahymena pyriformis
brenda
Xu, F.; Jerlstroem-Hultqvist, J.; Kolisko, M.; Simpson, A.; Roger, A.; Svaerd, S.; Andersson, J.
On the reversibility of parasitism adaptation to a free-living lifestyle via gene acquisitions in the diplomonad Trepomonas sp. PC1
BMC Biol.
14
62
2016
Trepomonas sp. PC1 (A0A146K6G2)
brenda
Banta, A.B.; Wei, J.H.; Welander, P.V.
A distinct pathway for tetrahymanol synthesis in bacteria
Proc. Natl. Acad. Sci. USA
112
13478-13483
2015
Tetrahymena thermophila (Q24FB1), Tetrahymena thermophila SB210 (Q24FB1)
brenda
Select items on the left to see more content.
EXTERNAL LINKS (specific for EC-Number 4.2.1.123)
html completed
Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.
About BRENDA
Help
Download
Contribution
member of
curated at
curated at
Server: brenda5 Ver: 69ad221-main (2022-06-24 14:26:09 +0200)