Information on EC 1.14.19.20 - DELTA7-sterol 5(6)-desaturase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
1.14.19.20
-
RECOMMENDED NAME
GeneOntology No.
DELTA7-sterol 5(6)-desaturase
-
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
a DELTA7-sterol + 2 ferrocytochrome b5 + O2 + 2 H+ = a DELTA5,7-sterol + 2 ferricytochrome b5 + 2 H2O
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
oxidation
redox reaction
reduction
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
7-dehydroporiferasterol biosynthesis
-
-
cholesterol biosynthesis I
-
-
cholesterol biosynthesis II (via 24,25-dihydrolanosterol)
-
-
cholesterol biosynthesis III (via desmosterol)
-
-
ergosterol biosynthesis I
-
-
ergosterol biosynthesis II
-
-
plant sterol biosynthesis
-
-
cholesterol biosynthesis
-
-
Steroid biosynthesis
-
-
Metabolic pathways
-
-
Biosynthesis of secondary metabolites
-
-
Biosynthesis of antibiotics
-
-
SYSTEMATIC NAME
IUBMB Comments
DELTA7-sterol,ferrocytochrome b5:oxygen oxidoreductase 5,6-dehydrogenating
This enzyme, found in eukaryotic organisms, catalyses the introduction of a double bond between the C5 and C6 carbons of the B ring of Delta7-sterols, to yield the corresponding Delta5,7-sterols. The enzymes from yeast, plants and vertebrates act on avenasterol, episterol, and lathosterol, respectively. The enzyme is located at the endoplasmic reticulum and is membrane bound.
CAS REGISTRY NUMBER
COMMENTARY hide
37255-37-1
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
metabolism
the enzyme is involved in ergosterol synthesis
physiological function
-
the enzyme is not essential for cell viability or the sparking function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
(24Z)-5alpha-stigmast-7,24(241)-dien-3beta-ol + O2 + reduced acceptor
(24Z)-stigmasta-5,7,24(241)-trien-3-beta-ol + acceptor + H2O
show the reaction diagram
-
-
-
?
(3beta,24R)-ergost-7-en-3-ol + ferrocytochrome b5 + O2 + H+
(3beta,24R)-ergosta-5,7-dien-3-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
14-methylfecosterol + ferrocytochrome b5 + O2 + H+
14-methylergosta-5,8,24(28)-trien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
?
5alpha-cholest-22-en-3beta-ol + ferrocytochrmoe b5 + H+ + O2
cholesta-5,22-dien-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
-
-
-
?
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+
cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
show the reaction diagram
5alpha-cholest-7-en-3beta-ol + ferrocytochrmoe b5 + H+ + O2
cholesta-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
NADH is more efficient than NADPH
-
-
?
5alpha-cholest-7-en-3beta-ol + ferrocytochrome b5 + H+ + O2
cholesta-5,7-dien-3beta-ol + ferricytochrmoe b5 + H2O
show the reaction diagram
-
-
-
?
5alpha-cholest-7-en-3beta-ol + ferrocytochrome b5 + H+ + O2
cholesta-5,7-dien-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
NADH is more efficient than NADPH
-
-
?
5alpha-cholest-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
? + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
5alpha-cholesta-7,22-dien-3beta-ol + ferrocytochrome b5 + H+ + O2
cholesta-5,7,22-trien-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
-
-
-
?
5alpha-cholestan-3beta-ol + ferrocytochrome b5 + H+ + O2
cholest-5-en-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
-
-
-
?
5alpha-ergost-7,24(241)-dien-3beta-ol + O2 + ferrocytochrome b5
ergosta-5,7,24(241)-trien-3beta-ol + H2O2 + ferricytochrome b5
show the reaction diagram
5alpha-ergosta-7,22-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosterol + ferricytochrome b5 + H2O
show the reaction diagram
5alpha-ergosta-7,24-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,7,24-trien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
5alpha-ergosta-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
apinasterol + ferrocytochrome b5 + O2 + H+
stigmast-5,7,22-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
avenasterol + ferrocytochrome b5 + O2 + H+
?
show the reaction diagram
-
-
-
-
?
cholest-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
cholest-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
DELTA7-avenasterol + O2 + ferrocytochrome b5
DELTA5,7-avenasterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
DELTA7-campesterol + O2 + ferrocytochrome b5
DELTA5,7-campesterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
DELTA7-sitosterol + O2 + ferrocytochrome b5
DELTA5,7-sitosterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
DELTA7-sitoststigmast-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
stigmast-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
DELTA7-sterol + ferrocytochrome b5 + O2 + H+
DELTA5,7-sterol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
episterol + ferrocytochrome b5 + O2 + H+
? + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
episterol + ferrocytochrome b5 + O2 + H+
ergosta-5,7,24(24)-trien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
episterol + ferrocytochrome b5 + O2 + H+
ergosta-5,7,24(28)-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
episterol + O2 + ferrocytochrome b5
DELTA5,7-episterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
ergosta-7,22-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,7,22-trien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
?
ergosta-7,22-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosterol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
?
ergosta-7,24(28)-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,7-dien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
ergosta-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,7-dien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
ergosta-8,22-dien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,8,22-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
ergosta-trien-3beta-ol + ferrocytochrome b5 + O2 + H+
ergosta-5,8,24(28)-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
ergosterol + ferrocytochrome b5 + O2 + H+
lanosterol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
fecosterol + ferrocytochrome b5 + O2 + H+
ergosta-5,7,24(28)-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
lanosterol + ferrocytochrome b5 + O2 + H+
? + ferricytochrome b5 + H2O
show the reaction diagram
lanosterol + ferrocytochrome b5 + O2 + H+
lanosta-5,8,24-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
lathosterol + ferrocytochrome b5 + O2 + H+
7-dehydrocholesterol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
lathosterol + ferrocytochrome b5 + O2 + H+
?
show the reaction diagram
-
-
-
-
?
lathosterol + O2+ ferrocytochrome b5
7-dehydrocholesterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
stigmast-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
stigmast-5,7-dien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
zymosterol + ferrocytochrome b5 + O2 + H+
cholesta-5,8,24-trien-3beta-ol + ferricyctochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
additional information
?
-
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
(3beta,24R)-ergost-7-en-3-ol + ferrocytochrome b5 + O2 + H+
(3beta,24R)-ergosta-5,7-dien-3-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
5alpha-cholest-22-en-3beta-ol + ferrocytochrmoe b5 + H+ + O2
cholesta-5,22-dien-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
C4PFX1
-
-
-
?
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+
cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
show the reaction diagram
5alpha-cholest-7-en-3beta-ol + ferrocytochrome b5 + H+ + O2
cholesta-5,7-dien-3beta-ol + ferricytochrmoe b5 + H2O
show the reaction diagram
C4PFX1
-
-
-
?
5alpha-cholesta-7,22-dien-3beta-ol + ferrocytochrome b5 + H+ + O2
cholesta-5,7,22-trien-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
C4PFX1
-
-
-
?
5alpha-cholestan-3beta-ol + ferrocytochrome b5 + H+ + O2
cholest-5-en-3beta-ol + ferricytochrome b5 + 2 H2O
show the reaction diagram
C4PFX1
-
-
-
?
cholest-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
cholest-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
DELTA7-sitoststigmast-7-en-3beta-ol + ferrocytochrome b5 + O2 + H+
stigmast-5,7-dien-3beta-ol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
DELTA7-sterol + ferrocytochrome b5 + O2 + H+
DELTA5,7-sterol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
episterol + ferrocytochrome b5 + O2 + H+
? + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
lathosterol + ferrocytochrome b5 + O2 + H+
7-dehydrocholesterol + ferricytochrome b5 + H2O
show the reaction diagram
-
-
-
-
?
lathosterol + O2+ ferrocytochrome b5
7-dehydrocholesterol + H2O + ferricytochrome b5
show the reaction diagram
-
-
-
-
?
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
cytochrome b5
-
NAD(P)H
NADPH
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Iron
required
additional information
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
(3S,20S)-20-N-(2-methylpropyl)carbamoylpregn-7-en-3beta-ol
-
; specific
(3S,20S)-20-N-(2-methylpropyl)carbamoylpregn-7-en-3beta-yl acetate
-
; specific for the enzyme. Prodrug, transformed into the 3beta-hydroxy derivative under in vitro conditions
(3S,20S)-20-N-butylcarbamoylpregn-7-en-3beta-ol
-
; specific
(3S,20S)-20-N-butylcarbamoylpregn-7-en-3beta-yl acetate
-
; specific for the enzyme. Prodrug, transformed into the 3beta-hydroxy derivative under in vitro conditions
(3S,20S)-20-N-ethylcarbamoylpregn-7-en-3beta-ol
-
-
(3S,20S)-20-N-ethylcarbamoylpregn-7-en-3beta-yl acetate
-
-
(3S,20S)-20-N-pentylcarbamoylpregn-7-en-3beta-ol
-
; specific
(3S,20S)-20-N-pentylcarbamoylpregn-7-en-3beta-yl acetate
-
; specific for the enzyme. Prodrug, transformed into the 3beta-hydroxy derivative under in vitro conditions
(3S,20S)-20-N-propylcarbamoylpregn-7-en-3beta-ol
-
-
(3S,20S)-20-N-propylcarbamoylpregn-7-en-3beta-yl acetate
-
-
(3S,20S)-20-N-tert-butylcarbamoylpregn-7-en-3beta-ol
-
; specific
(3S,20S)-20-N-tert-butylcarbamoylpregn-7-en-3beta-yl acetate
-
; specific for the enzyme. Prodrug, transformed into the 3beta-hydroxy derivative under in vitro conditions
1,10-phenanthroline
2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol
-
average content of 7-dehydrocholesterol in human primary hepatocytes after 2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol treatment is, 34.16 times higher than that in nontreated cells, indicating that DHCR7 is the major target (minor targets are human sterol DELTA14-reductase, sterol DELTA24-reductase, and sterol C5-desaturase). In vitro kinetic measurements show that the half-life of 2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol is at least 4.3 h. 2-(4-phenethylpiperazin-1-yl)-1-(pyridine-3-yl)ethanol does not induce CYP3A4 mRNA nor enzyme activity
4,5-dihydroxy-1,3-benzene-disulfonic acid
-
trivial name tiron, 0.5 mM, 80% inhibition
alpha-(2,4-dichlorophenyl)-alpha-phenyl-5-pyrimidine methanol
-
trivial name triarimol, weak inhibition
anti-cytochrome b5 antibodies
-
0.5 mg/mg protein. 36% inhibition
-
bathophenanthroline
-
0.5 mM, 71% inhibition
cyanide
cyctochrome c
-
-
-
dithiothreitol
-
1.0 mM, 55% inhibition
lathosterol side chain amides
-
synthesis and compound screening, influence of different sterol amides on inhibition of the enzyme, overview, lathosterol-derived amides with larger substituents, e.g. butyl, isobutyl, tert-butyl, pentyl, at the amide nitrogen are selective inhibitors of lathosterol oxidase, overview
-
menadione
-
32% residual actitivty at 0.05 mM
Salicylhydroxamic acid
-
-
salicylic hydroxamic acid
-
-
Tiron
-
21% residual activity at 1 mM
Triarimol
-
weak inhibition
additional information
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
squalene and sterol carrier protein
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.032 - 0.244
5alpha-Cholest-7-en-3beta-ol
0.08
apinasterol
-
at pH 7.6 and 30C
-
0.14
avenasterol
-
at pH 7.6 and 30C
0.0105
episterol
-
at pH 7.6 and 30C
0.115
lathosterol
-
at pH 7.6 and 30C
0.67
stigmast-7-en-3beta-ol
-
at pH 7.6 and 30C
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00033
(3S,20S)-20-N-(2-methylpropyl)carbamoylpregn-7-en-3beta-ol
Homo sapiens
-
inhibition of total cholesterol prduction
0.00045
(3S,20S)-20-N-(2-methylpropyl)carbamoylpregn-7-en-3beta-yl acetate
Homo sapiens
-
inhibition of total cholesterol prduction
0.0007
(3S,20S)-20-N-butylcarbamoylpregn-7-en-3beta-ol
Homo sapiens
-
inhibition of total cholesterol prduction
0.00091
(3S,20S)-20-N-butylcarbamoylpregn-7-en-3beta-yl acetate
Homo sapiens
-
inhibition of total cholesterol prduction
0.00116
(3S,20S)-20-N-pentylcarbamoylpregn-7-en-3beta-ol
Homo sapiens
-
inhibition of total cholesterol prduction
0.0011
(3S,20S)-20-N-pentylcarbamoylpregn-7-en-3beta-yl acetate
Homo sapiens
-
inhibition of total cholesterol prduction
0.00105
(3S,20S)-20-N-tert-butylcarbamoylpregn-7-en-3beta-ol
Homo sapiens
-
inhibition of total cholesterol prduction
0.00095
(3S,20S)-20-N-tert-butylcarbamoylpregn-7-en-3beta-yl acetate
Homo sapiens
-
inhibition of total cholesterol prduction
2
1,10-phenanthroline
Zea mays
-
at pH 7.6 and 30C
0.015
cyanide
Zea mays
-
at pH 7.6 and 30C
0.008
cyctochrome c
Zea mays
-
at pH 7.6 and 30C
-
0.5
Salicylhydroxamic acid
Zea mays
-
at pH 7.6 and 30C
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.0013
-
crude enzyme, at pH 8.0 and 37C
0.022
-
after 17.7fold purification, at pH 8.0 and 37C
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
primary hepatocytes are used for analysis
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
-
-
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
-
mRNA expression
Manually annotated by BRENDA team
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
x * 30000, SDS-PAGE
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
extremely labile
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
0C, 24 h, 30% loss of activity
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
partial purification by DEAE cellulose column chromatography and 6-amino-hexyl-Sepharose column chromatography
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
; expression in null mutant erg3 of Saccharomyces cerevisiae
expressed in a Saccharomyces cerevisiae erg3-deficient mutant strain
expressed in an C-5(6) sterol desaturase erg3-deficient mutant of Saccharomyces cerevisia
expressed in an erg3-defective mutant of Saccharomyces crevisiae
-
expressed in Arabidopsis thaliana deficient in DELTA7-sterol-C-5-desaturase
-
expressed in Saccharomyces cerevisiae strain erg3
-
expression in Saccharomyces cerevisiae erg3 mutant
wild-type enzyme and ste1 mutant enzyme expressed in Sacharomyces cerevisiae erg3 mutant, wild-type enzyme overexpressed in Arabidopsis ste1 mutant
-
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
G234A
inactive mutant enzyme; no activity
G234D
2% of wild-type activity; low activity
H147E
inactive mutant enzyme; no activity
H147L
inactive mutant enzyme; no activity
H151E
inactive mutant enzyme; no activity
H151l
inactive mutant enzyme; no activity
H161E
inactive mutant enzyme; no activity
H161L
inactive mutant enzyme; no activity
H164L
inactive mutant enzyme; no activity
H165L
inactive mutant enzyme; no activity
H203L
13% of wild-type activity; reduced activity
H222E
6% of wild-type activity; reduced activity
H222L
inactive mutant enzyme; no activity
H238E
inactive mutant enzyme; no activity
H238L
inactive mutant enzyme; no activity
H241L
inactive mutant enzyme; no activity
H242L
inactive mutant enzyme; no activity
K115L
2times higher activity than wild-type; Km-value for 5alpha-cholest-7-en-3beta-ol is 2.8fold higher than that of wild-type activity
P175A
as active as wild-type enzyme; wild-type activity
P175V
4times higher activity than wild-type; Km-value for 5alpha-cholest-7-en-3beta-ol is 2.7fold higher than that of wild-type activity
P201A
20% of wild-type activity; 25% of wild-type activity
T114I
wild-type activity
T114I |
Km-value for 5alpha-cholest-7-en-3beta-ol is 7.5fold higher than that of wild-type activity
T114S
28times higher activity than wild-type; Km-value for 5alpha-cholest-7-en-3beta-ol is 7.6fold higher than that of wild-type activity
L193R
the mutation impairs enzyme function
additional information