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Information on EC 5.5.1.9 - Cycloeucalenol cycloisomerase and Organism(s) Arabidopsis thaliana and UniProt Accession Q9M643
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5.5.1.9 Cycloeucalenol cycloisomeraseIUBMB Comments
Opens the cyclopropane ring of a number of related 4alpha-methyl-9beta-19-cyclosterols, but not those with a 4beta-methyl group, with formation of an 8(9) double bond. Involved in the synthesis of plant sterols.
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Word Map
- 5.5.1.9
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carbocationic
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fungicide
- ergosterol
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high-energy
- cycloartenol
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carbonium
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7-sterol
- cyclase
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beta-ol
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14-reductase
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auxotroph
- maize
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presumptive
The taxonomic range for the selected organisms is: Arabidopsis thaliana
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria
Synonyms
cycloeucalenol-obtusifoliol isomerase, cycloeucalenol cycloisomerase, cycloeucalenol isomerase, atcpi, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
Cycloeucalenol isomerase
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-
-
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Cycloeucalenol--obtusifoliol isomerase
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-
-
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Cycloeucalenol-obtusifoliol isomerase
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-
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Cyclopropyl sterol isomerase
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Isomerase, cycloeucalenol-obtusifoliol
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PATHWAY SOURCE
PATHWAYS
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-, -, -, -, -
SYSTEMATIC NAME
IUBMB Comments
Cycloeucalenol lyase (cyclopropane-decyclizing)
Opens the cyclopropane ring of a number of related 4alpha-methyl-9beta-19-cyclosterols, but not those with a 4beta-methyl group, with formation of an 8(9) double bond. Involved in the synthesis of plant sterols.
CAS REGISTRY NUMBER
COMMENTARY
60496-19-7
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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
cycloeucalenol
obtusifoliol
converts pentacyclic cycloprolylsterols to conventional tetracyclic sterols
-
?
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
cycloeucalenol
obtusifoliol
converts pentacyclic cycloprolylsterols to conventional tetracyclic sterols
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?
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.077
cycloeucalenol
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mutant E29D, 30°C, pH not specified in the publication, Vmax: 0.24 nmol/h/mg
0.078
cycloeucalenol
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mutant D260H, 30°C, pH not specified in the publication, Vmax: 0.35 nmol/h/mg
0.093
cycloeucalenol
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mutant E29H, 30°C, pH not specified in the publication, Vmax: 0.33 nmol/h/mg
0.135
cycloeucalenol
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mutant W112L, 30°C, pH not specified in the publication, Vmax: 14.7 nmol/h/mg
0.167
cycloeucalenol
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wild-type, 30°C, pH not specified in the publication, Vmax: 22 nmol/h/mg
0.377
cycloeucalenol
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mutant F111L, 30°C, pH not specified in the publication, Vmax: 4.7 nmol/h/mg
0.409
cycloeucalenol
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mutant D260E, 30°C, pH not specified in the publication, Vmax: 44 nmol/h/mg
0.496
cycloeucalenol
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mutant T113S, 30°C, pH not specified in the publication, Vmax: 26 nmol/h/mg
0.52
cycloeucalenol
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mutant F117L, 30°C, pH not specified in the publication, Vmax: 5.3 nmol/h/mg
0.622
cycloeucalenol
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mutant G108A, 30°C, pH not specified in the publication, Vmax: 11.4 nmol/h/mg
1.53
cycloeucalenol
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mutant T113A, 30°C, pH not specified in the publication, Vmax: 4.9 nmol/h/mg
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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). CCI1_ARATH
280
6
32644
Swiss-Prot
other Location (Reliability: 4)
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
D260E
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 92%, wild-type: 100%. Relative activity: 135% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type. Mutant shows 6% activity with 24-methylene-24-dihydro-cycloartenol (wild-type 0%)
D260H
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 61%, wild-type: 100%. Relative activity: 5.2% (wild-type: 100%). Km (cycloeucalenol) decreased compared to wild-type
D260V
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 0%, wild-type: 100%. Relative activity: below 1.5% (wild-type: 100%)
D260Y
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 22%, wild-type: 100%. Relative activity: 0.7% (wild-type: 100%)
E29D
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 65%, wild-type: 100%. Relative activity: 3.8% (wild-type: 100%). Km (cycloeucalenol) decreased compared to wild-type
E29H
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 33%, wild-type: 100%. Relative activity: 3.5% (wild-type: 100%). Km (cycloeucalenol) decreased compared to wild-type
E29K
E29V
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 0%, wild-type: 100%. Relative activity: below 0.5% (wild-type: 100%)
E54V
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 94%, wild-type: 100%
E58V
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 91%, wild-type: 100%
E60V
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 83%, wild-type: 100%
F111L
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 88%, wild-type: 100%. Relative activity: 31% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type
F116L
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 37%, wild-type: 100%. Relative activity: 4.7% (wild-type: 100%)
F117L
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 89%, wild-type: 100%. Relative activity: 28% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type
G108A
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 92%, wild-type: 100%. Relative activity: 90% (wild-type: 100%)
G108E
G108V
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 6%, wild-type: 100%. Relative activity: 1.7% (wild-type: 100%)
G28E
G28V
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 46%, wild-type: 100%. Relative activity: 1.6% (wild-type: 100%)
H114L
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 85%, wild-type: 100%. Relative activity: 5.2% (wild-type: 100%)
N109A
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 76%, wild-type: 100%. Relative activity: 4.6% (wild-type: 100%)
T113A
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 69%, wild-type: 100%. Relative activity: 7.2% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type
T113I
T113S
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 98%, wild-type: 100%. Relative activity: 73% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type
W112E
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 77%, wild-type: 100%. Relative activity: 5.8% (wild-type: 100%)
W112K
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 47%, wild-type: 100%. Relative activity: 1.8% (wild-type: 100%)
W112L
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 86%, wild-type: 100%. Relative activity: 49% (wild-type: 100%). Km (cycloeucalenol) decreased compared to wild-type. Mutant shows 69% activity with 24-methylene-24-dihydro-cycloartenol (wild-type 0%), 10% activity with cycloartenol (wild-type 0%). 32% activity with cycloartanol (wild-type 0%), 15% activity with 4beta-methyl-24-dihydro-cycloeucalenol (wild-type 0%)
Y110L
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 64%, wild-type: 100%. Relative activity: 2.8% (wild-type: 100%)
Y115L
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 83%, wild-type: 100%. Relative activity: 4.3% (wild-type: 100%)
E29K
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cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 1.7%, wild-type: 100%. Relative activity: below 0.5% (wild-type: 100%)
E29K
-
in vivo conversion of cycloeucalenol into ergosterol and in vitro CPI activity in Saccharomyces cerevisiae erg7 transformants carrying Arabidopsis thaliana mutant CPI: 1.7% relative ergosterol synthesis (wild-type: 100%), below 0.5% in vitro microsomal CPI activity (wild-type: 100%)
G108E
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 0%, wild-type: 100%. Relative activity: below 0.5% (wild-type: 100%). Km (cycloeucalenol) increased compared to wild-type
G108E
-
in vivo conversion of cycloeucalenol into ergosterol and in vitro CPI activity in Saccharomyces cerevisiae erg7 transformants carrying Arabidopsis thaliana mutant CPI: 0% relative ergosterol synthesis (wild-type: 100%), below 0.5% in vitro microsomal CPI activity (wild-type: 100%)
G28E
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 15%, wild-type: 100%. Relative activity: 1% (wild-type: 100%)
G28E
-
in vivo conversion of cycloeucalenol into ergosterol and in vitro CPI activity in Saccharomyces cerevisiae erg7 transformants carrying Arabidopsis thaliana mutant CPI: 15% relative ergosterol synthesis (wild-type: 100%), 1% in vitro microsomal CPI activity (wild-type: 100%)
T113I
-
cycloeucalenol conversion into ergosterol in Saccharomyces cerevisiae erg7 transformants carrying mutagenized AtCPI, relative ergosterol synthesis: 66%, wild-type: 100%. Relative activity: 3.1% (wild-type: 100%)
T113I
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in vivo conversion of cycloeucalenol into ergosterol and in vitro CPI activity in Saccharomyces cerevisiae erg7 transformants carrying Arabidopsis thaliana mutant CPI: 66% relative ergosterol synthesis (wild-type: 100%), below 2.4% in vitro microsomal CPI activity (wild-type: 100%)
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Lovato, M.A.; Hart, E.A.; Segura, M.J.R.; Giner, J.L.; Matsuda, S.P.T.
Functional cloning of an Arabidopsis thaliana cDNA encoding cycloeucalenol cycloisomerase
J. Biol. Chem.
275
13394-13397
2000
Arabidopsis thaliana (Q9M643), Arabidopsis thaliana
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