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Information on EC 1.1.1.270 - 3beta-hydroxysteroid 3-dehydrogenase
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1.1.1.270 3beta-hydroxysteroid 3-dehydrogenaseIUBMB Comments
The enzyme acts on multiple 3beta-hydroxysteroids. Participates in the biosynthesis of zemosterol and cholesterol, where it catalyses the reaction in the opposite direction to that shown. The mammalian enzyme is bifunctional and also catalyses EC 1.1.1.62, 17beta-estradiol 17-dehydrogenase .
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Word Map
- 1.1.1.270
-
steroidogenic
- testosterone
- androgen
- progesterone
-
steroidogenesis
- adrenal
- leydig
- star
- cyp11a1
- testicular
- p450scc
- aromatase
- lutein
- lh
- pregnenolone
- androstenedione
- dehydroepiandrosterone
- akr1c1
-
granulosa
- trilostane
- 17alpha-hydroxylase
- 3betahsd
- hsd3b2
- dheas
- dihydrotestosterone
-
lhcgr
- srd5a1
- p450arom
-
5alpha-reductase
- 21-hydroxylase
- 3-ketosteroids
-
scarb1
- hsd11b1
-
22r-hydroxycholesterol
- 5alpha-dihydrotestosterone
-
neurosteroids
-
20alpha-hydroxysteroid
-
11beta-hydroxylase
- cyp21
- 3alpha-hsds
- insl3
-
intratesticular
-
lh-stimulated
-
adrenarche
- 17-hydroxypregnenolone
- medicine
- 17alpha-hydroxyprogesterone
-
delta5
-
pre-receptor
- synthesis
- analysis
- 20alpha-hsd
- 17alpha-hydroxylase/17,20-lyase
The enzyme appears in viruses and cellular organisms
Synonyms
3beta-hydroxysteroid dehydrogenase, hsd3b1, akr1c2, hsd17b7, erg27, 3beta-hsd1, 3-ketosteroid reductase, 3beta-hsd2, 3-ketoreductase, erg27p, 
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SYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
17beta-hydroxysteroid dehydrogenase type 7
3-keto reducing enzyme
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-
-
-
3-keto reductase
-
-
-
-
3-ketoreductase
-
-
-
-
3-ketosteroid reductase
3-KSR
-
-
-
-
3-oxo steroid reductase
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-
-
-
3-oxosteroid reductase
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-
-
-
3beta-HSD
3beta-HSD1
3beta-hydroxysteroid dehydrogenase
3beta-hydroxysteroid dehydrogenase type 1
AKR1C1
Erg27
HSD17B7
reductase, 3-oxo steroid
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-
-
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steroid-3-ketoreductase
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-
-
-
sterone-reducing enzyme
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-
-
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3-ketosteroid reductase
-
-
-
-
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
a 3beta-hydroxysteroid + NADP+ = a 3-oxosteroid + NADPH + H+
also acts on 5alpha-cholest-7-en-3-one
-
-
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a 3beta-hydroxysteroid + NADP+ = a 3-oxosteroid + NADPH + H+
stereoselectivity : #1,4,5# catalyzes reduction of the 3-keto group to a 3beta-hydroxyl group <5,6,7>
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a 3beta-hydroxysteroid + NADP+ = a 3-oxosteroid + NADPH + H+
stereoselectivity : #1,4,5# catalyzes reduction of the 3-keto group to a 3beta-hydroxyl group <5,6,7>
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a 3beta-hydroxysteroid + NADP+ = a 3-oxosteroid + NADPH + H+
residues Leu/Val54, Tyr55, His117, Val128, Ile129, His222, and Trp227 are involved in substrate binding, Tyr55, Asp50, Lys84, and His117 form the catalytic tetrad, Tyr55 and His117 together with NADP+ form an oxyanion hole through hydrogen bond networks, molecular docking simulations, detailed overview
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
oxidation
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oxidation of 3beta-hydroxy-steroids poorly catalyzed for a few substrates
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redox reaction
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-
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reduction
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ketone reduction
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PATHWAY SOURCE
PATHWAYS
BRENDA
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SYSTEMATIC NAME
IUBMB Comments
3beta-hydroxysteroid:NADP+ 3-oxidoreductase
The enzyme acts on multiple 3beta-hydroxysteroids. Participates in the biosynthesis of zemosterol and cholesterol, where it catalyses the reaction in the opposite direction to that shown. The mammalian enzyme is bifunctional and also catalyses EC 1.1.1.62, 17beta-estradiol 17-dehydrogenase [4].
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CAS REGISTRY NUMBER
COMMENTARY
42616-29-5
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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
17alpha-hydroxypregnenolone + NADH + H+
17alpha-hydroxyprogesterone + NAD+
-
-
-
-
?
2 17beta-hydroxy-5alpha-androstan-3-one + 2 NADPH + 2 H+
5alpha-androstane-3beta,17beta-diol + 5alpha-androstane-3alpha,17beta-diol + 2 NADP+
24-ethylidenelophenone + NADPH
24-ethylidenelophenol + NADP+
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oxidation: poor
-
r
24-methylenecycloartanone + NADPH
24-methylenecycloartanol + NADP+
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7% compared with cholest-7-en-3-one, DELTA7-cholestenone
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ir
24-methylenelophenone + NADPH
24-methylenelophenol + NADP+
-
35% compared with cholest-7-en-3-one, DELTA7-cholestenone
-
?
24-methylenepollinastanone + NADPH + acetate
24-methylenepollinastanol + NADP+
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70% compared with cholest-7-en-3-one, DELTA7-cholestenone
-
?
24RS-dihydrocycloeucalenone + NADPH
24RS-dihydrocycloeucalenol + NADP+
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53% compared with cholest-7-en-3-one, DELTA7-cholestenone
-
?
3-keto-5alpha-androstane steroids + NADPH
3beta-hydroxy-5alpha-androstane steroids + NADP+
-
-
-
ir
3-oxocholic acid + NAD(P)H + H+
cholic acid + NAD(P)+
10.3% of the activity compared to the substrate isodeoxycholic acid
-
-
r
3-oxodeoxycholic acid + NAD(P)H + H+
isodeoxycholic acid + NAD(P)+
55.2% of the activity compared to the substrate isodeoxycholic acid
-
-
r
3alpha-androstanediol + NAD+
? + NADH
AKR1C2 and AKR1C4 act as 3alpha-hydroxysteroid oxidase, AKR1C3 predominantly acts as 17beta-hydroxysteroid oxidase catalyzing the conversion of 3alpha-diol to androsterone, negligible activity with the 3beta-androstanediol
-
-
?
4,4-gem-dimethyl-5alpha-cholest-7-en-3-one + NADPH
4,4-gem-dimethyl-5alpha-cholest-7-en-3beta-ol + NADP+
4alpha-methyl-5alpha-cholest-7-en-3-one + NADPH
4alpha-methyl-5alpha-cholest-7-en-3beta-ol + NADP+
-
best substrate, reduction consistently about two times greater for monosubstituted steroid
-
?
4alpha-methylfecosterone + NADPH + H+
4alpha-methylfecosterol + NADP+
-
-
4alpha-methylfecosterol is further converted to ergosterol
-
?
4alpha-methylzymosterol + NADP+
3-dehydro-4-methylzymosterol + NADPH + H+
-
-
-
-
?
4beta-methyl-28-nor-24RS-dihydrocycloeucalenone + NADPH
4beta-methyl-28-nor-24RS-dihydrocycloeucalenol + NADP+
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27% compared with cholest-7-en-3-one, DELTA7-cholestenone
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?
5alpha-androstan-3,17-dione + NADPH + H+
5alpha-androstan-3beta-ol-17-one + NADP+
-
-
-
-
r
5alpha-dihydrotestosterone + NADPH + H+
3beta,17beta-dihydroxy-5alpha-androstane + NADP+
-
-
-
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r
5alpha-dihydrotestosterone + NADPH + H+
5alpha-androstan-3beta,17beta-diol + NADP+
i.e. DHT, reductive 3beta-HSD activity of AKR1C1 yielding the 3beta,17-diol, preferred reaction
-
-
?
5alpha-pregnan-3,20-dione + NADPH + H+
5alpha-pregnane-3beta-ol-20-one + NADP+
-
-
-
-
r
5alpha-pregnane-21-ol-3,20-dione + NADPH + H+
5alpha-pregnane-3beta,21-diol-20-one + NADP+
-
-
-
-
r
5beta-androstan-3,17-dione + NADPH + H+
5beta-androstan-3beta-ol-17-one + NADP+
-
-
-
-
r
5beta-androstan-3beta-ol-17-one + NADP+
5beta-androstan-3,17-dione + NADPH + H+
-
-
-
-
r
5beta-androstane-3beta,17beta-diol + NADP+
5beta-androstane-17beta-ol-3-one + NADPH + H+
-
-
-
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r
5beta-cholanic acid-3,7-dione + NADPH + H+
5beta-cholanic acid-3beta-ol-7-one + NADP+
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-
-
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r
5beta-dihydrocorticosterone + NADPH + H+
(3beta,5beta,11beta)-3,11,21-trihydroxypregnan-20-one + NADP+
-
-
-
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r
5beta-dihydrotestosterone + NADPH + H+
3beta,17beta-dihydroxy-5beta-androstane + NADP+
-
-
-
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r
5beta-hydroxy-5beta cholanic acid + NADP+
3-oxo-5-beta-cholanic acid + NADPH + H+
-
-
-
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r
5beta-pregnan-3,20-dione + NADPH + H+
5beta-pregnane-3beta-ol-20-one + NADP+
-
-
-
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r
5beta-pregnane-20-ol-3-one + NADPH + H+
5beta-pregnane-3beta,20-diol + NADP+
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-
-
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r
5beta-pregnane-21-ol-3,20-dione + NADPH + H+
5beta-pregnane-3beta,21-diol-20-one + NADP+
-
-
-
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r
5beta-pregnane-3beta,20alpha-diol + NADP+
5beta-pregnane-20alpha-ol-3-one + NADPH + H+
-
-
-
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r
5beta-pregnane-3beta,20beta-diol + NADP+
5beta-pregnane-20beta-ol-3-one + NADPH + H+
-
-
-
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r
5beta-pregnane-3beta,21-diol-20-one + NADP+
5beta-pregnane-21-ol-3,20-dione + NADPH + H+
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-
-
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r
5beta-pregnane-3beta-ol-20-one + NADP+
5beta-pregnan-3,20-dione + NADPH + H+
-
-
-
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r
avenastenone + NADPH
avenasterol + NADP+
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more than 72% compared with cholest-7-en-3-one, DELTA7-cholestenone
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?
chenodeoxycholic acid + NAD(P)+
3-oxo-chenodeoxycholic acid + NAD(P)H + H+
11.7% of the activity compared to the substrate isodeoxycholic acid
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-
r
cholest-7-en-3-one + NADPH
3beta-hydroxy-cholest-7-ene + NADP+
-
DELTA7-cholestenone, best substrate
DELTA7-cholesterol
ir
cholestanone + NADPH
cholestanol + NADP+
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57% compared with cholest-7-en-3-one, DELTA7-cholestenone
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?
cholic acid + NAD(P)+
3-oxo-cholic acid + NAD(P)H + H+
12.7% of the activity compared to the substrate isodeoxycholic acid
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-
r
cycloartenone + NADPH
cycloartenol + NADP+
-
7% compared with cholest-7-en-3-one, DELTA7-cholestenone
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ir
cyclolaudenone + NADPH
cyclolaudenol + NADP+
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10% compared with cholest-7-en-3-one, DELTA7-cholestenone
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?
deoxycholic acid + NAD(P)+
3-oxo-deoxycholic acid + NAD(P)H + H+
22.4% of the activity compared to the substrate isodeoxycholic acid
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r
glycochenodeoxycholic acid + NAD(P)+
? + NAD(P)H + H+
13.2% of the activity compared to the substrate isodeoxycholic acid
-
-
r
glycocholic acid + NAD(P)+
? + NAD(P)H + H+
12.4% of the activity compared to the substrate isodeoxycholic acid
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-
r
glycodeoxycholic acid + NAD(P)+
? + NAD(P)H + H+
20.6% of the activity compared to the substrate isodeoxycholic acid
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r
isodeoxycholic acid + NADP+
3-oxodeoxycholic acid + NADPH + H+
-
-
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r
progesterone + NADPH
pregn-4-ene-20alpha-ol-3-one + NADP+
i.e. pregn-4-ene-3,20-dione
-
-
?
pyridine-3-aldehyde + NADP+
pyridin-3-ylmethanol + NADPH + H+
-
-
-
-
?
spinastenone + NADPH
spinasterol + NADP+
-
32% compared with cholest-7-en-3-one, DELTA7-cholestenone
-
?
taurochenodeoxycholic acid + NAD(P)+
? + NAD(P)H + H+
11.5% of the activity compared to the substrate isodeoxycholic acid
-
-
r
taurocholic acid + NAD(P)+
? + NAD(P)H + H+
11.5% of the activity compared to the substrate isodeoxycholic acid
-
-
r
taurodeoxychloic acid + NAD(P)+
? + NAD(P)H + H+
21.8% of the activity compared to the substrate isodeoxycholic acid
-
-
r
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one + NADPH
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-ol + NADP+
(4-methyl)zymosterone + NADPH + H+
(4-methyl)zymosterol + NADP+
cholesterol pathway
-
-
?
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
5alpha-dihydrotestosterone
androstanediol, 5alpha-androstane-3alpha,17beta-diol or 5alpha-androstane-3beta,17beta-diol
?
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
DHT
androstanediol, 5alpha-androstane-3alpha,17beta-diol or 5alpha-androstane-3beta,17beta-diol
?
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
dihydrotestosterone
androstanediol, 5alpha-androstane-3alpha,17beta-diol or 5alpha-androstane-3beta,17beta-diol
?
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
5alpha-dihydrotestosterone
androstanediol, corresponding 3beta-hydroxysteroid
ir
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
DHT
androstanediol, corresponding 3beta-hydroxysteroid
ir
17beta-hydroxy-5alpha-androstan-3-one + NADPH
5alpha-androstane-3beta,17beta-diol + NADP+
-
dihydrotestosterone
androstanediol, corresponding 3beta-hydroxysteroid
ir
2 17beta-hydroxy-5alpha-androstan-3-one + 2 NADPH + 2 H+
5alpha-androstane-3beta,17beta-diol + 5alpha-androstane-3alpha,17beta-diol + 2 NADP+
-
the rates of 3alpha-diol versus 3beta-diol formation varies significantly among the isoforms. AKR1C1 predominantly catalyzes the formation of 3beta-diol, whereas AKR1C2 and AKR1C4 predominantly catalyze the formation of 3alpha-diol. AKR1C3 shows relatively low reductive activity towards 17beta-hydroxy-5alpha-androstan-3-one, in which 3alpha-diol and 3beta-diol is formed in almost equal amounts
-
?
2 17beta-hydroxy-5alpha-androstan-3-one + 2 NADPH + 2 H+
5alpha-androstane-3beta,17beta-diol + 5alpha-androstane-3alpha,17beta-diol + 2 NADP+
AKR1cs are a source of beta-tetrahydrosteroids. This is of physiological significance because the formation of 3beta-diol in contrast to 3alpha-diol is virtually irreversible, the 3beta-diol is a pro-apoptotic ligand for estrogen receptor beta, and 3beta-tetrahydrosteroids act as gamma-aminobutyric acid type A receptor antagonists
-
-
?
4,4-gem-dimethyl-5alpha-cholest-7-en-3-one + NADPH
4,4-gem-dimethyl-5alpha-cholest-7-en-3beta-ol + NADP+
-
-
-
?
4,4-gem-dimethyl-5alpha-cholest-7-en-3-one + NADPH
4,4-gem-dimethyl-5alpha-cholest-7-en-3beta-ol + NADP+
-
-
-
?
5alpha-androstane-3,17-dione + NADPH
epi-androsterone + NADP+
-
3-ketosteroid reductase activity of the human 3(alpha-beta)-hydroxysteroid epimerase, stereoselective reduction
epi-ADT
?
5alpha-androstane-3,17-dione + NADPH
epi-androsterone + NADP+
-
5alpha-dione
epi-ADT
?
5alpha-androstane-3,17-dione + NADPH
epi-androsterone + NADP+
-
A-dione
-
-
ir
5alpha-dihydrotestosterone + NADPH + H+
5alpha-androstan-3alpha,17beta-diol + NADP+
-
-
-
-
?
5alpha-dihydrotestosterone + NADPH + H+
5alpha-androstan-3alpha,17beta-diol + NADP+
-
in prostate cells AKR1C2 acts as a 3-ketosteroid reductase to eliminate 5alpha-dihydrotestosterone and prevents activation of androgen receptor. AKR1C2 does not act as an oxidase due to either potent product inhibition by NADPH or because it cannot surmount the oxidative 17beta-hydroxysteroid dehydrogenase present. AKR1C2 is not a source of 5alpha-dihydrotestosterone in PC-3 cells
-
-
?
5alpha-dihydrotestosterone + NADPH + H+
5alpha-androstan-3alpha,17beta-diol + NADP+
i.e. DHT, reductive 3alpha-HSD activity of AKR1C1 yielding the 3alpha,17-diol, low activity
-
-
?
cycloeucalenone + NADPH + H+
cycloeucalenol + NADP+
-
putative endogenous substrate for sterone reductase
reverse oxidation: about 35% of forward reductase rate, 17-(4-isopropyl-1-methyl-pent-4-enyl)-4,13,14-trimethyl-tetradecahydro-cyclopropa[9,10]cyclopenta[a]phenanthren-3beta-ol
r
cycloeucalenone + NADPH + H+
cycloeucalenol + NADP+
-
68% compared with cholest-7-en-3-one, DELTA7-cholestenone
reverse oxidation: about 35% of forward reductase rate, 17-(4-isopropyl-1-methyl-pent-4-enyl)-4,13,14-trimethyl-tetradecahydro-cyclopropa[9,10]cyclopenta[a]phenanthren-3beta-ol
r
DELTA7-chondrillastenone + NADPH
DELTA7-chondrillasterol + NADP+
-
70% compared with cholest-7-en-3-one, DELTA7-cholestenone
17-(4-ethyl-1,5-dimethyl-hex-2-enyl)-10,13-dimethyl-2,3,4,5,6,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3beta-ol
?
DELTA7-chondrillastenone + NADPH
DELTA7-chondrillasterol + NADP+
-
5alpha,28beta(H)-stigmasta-7,22-dien-3-one
17-(4-ethyl-1,5-dimethyl-hex-2-enyl)-10,13-dimethyl-2,3,4,5,6,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3beta-ol
?
dihydrotestosterone + NADPH + H+
5alpha-androstane-3beta,17beta-diol + NADP+
-
-
-
?
dihydrotestosterone + NADPH + H+
5alpha-androstane-3beta,17beta-diol + NADP+
steroid hormone pathway
-
-
?
obtusifolione + NADPH
obtusifoliol + NADP+
-
4,14-dimethyl-ergosta-8,24(28)-dien-3-one
4,14-dimethyl-ergosta-8,24(28)-dien-3-ol
?
obtusifolione + NADPH
obtusifoliol + NADP+
-
43% compared with cholest-7-en-3-one, DELTA7-cholestenone
4,14-dimethyl-ergosta-8,24(28)-dien-3-ol
?
obtusifolione + NADPH
obtusifoliol + NADP+
-
4,14-dimethyl-ergosta-8,24(28)-dien-3-one
4,14-dimethyl-ergosta-8,24(28)-dien-3-ol
?
progesterone + NADPH + H+
4-pregnen-3beta-ol-20-one + NADP+
steroid hormone pathway
-
-
?
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one + NADPH
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-ol + NADP+
i.e. tibolone, a synthetic hormone
-
-
?
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one + NADPH
[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-ol + NADP+
-
i.e. tibolone, a synthetic hormone
reaction product determination and analysis
-
?
additional information
?
-
-
substrate for 3-ketoreductase in the first sterol C-4 demethylation cycle is 4alpha-methylfecosterone, whereas that for the second C-4 demethylation cycle is fecosterone
-
-
?
additional information
?
-
-
NADPH-dependent 3-ketosteroid reductase catalyzes reduction of the 3-keto group to a 3beta-hydroxyl group
-
-
?
additional information
?
-
-
enzyme of sterol, ergosterol, biosynthesis, enzyme catalyzes last step in demethylation at C-4
-
-
?
additional information
?
-
-
3-ketosteroid reductase activity of the human 3(alpha-beta)-hydroxysteroid epimerase catalyzes reduction of 3-ketosteroids to form 3beta-hydroxysteroids
-
-
?
additional information
?
-
-
HSD17B7 participates in postsqualene cholesterol biosynthesis, HSD17B7 is a novel candidate for inborn errors of cholesterol metabolism
-
-
?
additional information
?
-
-
tibolone is used to treat climacteric symptoms and prevent osteoporosis, it exerts tissue-selective effects via site-specific metabolism into 3alpha- and 3beta-hydroxymetabolites and a DELTA4-isomer, In Hep-G2 cell cytosol and intact cells tibolone is exclusively reduced to 3beta-hydroxytibolone, tibolone metabolism in human liver is catalyzed by 3alpha/3beta-hydroxysteroid dehydrogenase activities of the four isoforms of the aldo-keto reductase (AKR)1C subfamily, overview
-
-
?
additional information
?
-
AKR1C1 is a cytosolic hydroxysteroid dehydrogenase, that reduces 3-ketosteroids and 20-ketosteroids, overview, molecular docking simulations with generation of docking targets, overview
-
-
?
additional information
?
-
-
AKR1C1 is a cytosolic hydroxysteroid dehydrogenase, that reduces 3-ketosteroids and 20-ketosteroids, overview, molecular docking simulations with generation of docking targets, overview
-
-
?
additional information
?
-
-
comparison of substrate specificity and enantioselectivity of AKR1C isozymes, overview
-
-
?
additional information
?
-
-
both isoforms of the enzyme catalyze the conversion of 3beta-hydroxy-5-ene-steroids (dehydroepiandrosterone, 17alpha-hydroxypregnenolone, pregnenolone) to 3-oxo-4-ene-steroids (androstenedione, 17alpha-hydroxyprogestrone, progesterone) on a single, dimeric protein containing both enzyme activities
-
-
?
additional information
?
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enzyme might form complexes with other proteins, including possibly DNA-binding proteins, under low ionic strength conditions
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additional information
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HSD17B7 participates in postsqualene cholesterol biosynthesis
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additional information
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the enzyme, termed AKR1B19, acts not only as a reductase for reactive carbonyl compounds derived from lipid peroxidation like AR-like proteins of other species, but also as a superior reductive 3beta-HSD for 3-keto-5alpha/beta-dihydro-C19/C21/C24-steroids
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?
additional information
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substrate specificity of the bifunctional enzyme, for carbonyl compounds and steroids, overview. No reductase activity is observed for 17- and 20-ketosteroids, DELTA4-3-ketosteroids (testosterone, 4-androstene-3,17-dione and progesterone), and prostaglandins (D2, E2, and A1). In the reverse reaction, the enzyme oxidizes 3beta-hydroxy-5alpha/beta-dihydrosteroids, but shows no significant dehydrogenase activity for DELTA5-3beta-hydroxysteroids (dehydroepiandrosterone, pregnenolone, and 5-pregnene-3beta,20alpha-diol) and 3alpha-hydroxysteroids (5alpha/beta-androstan-3alpha-ol-17-ones, 5alpha/beta-androstane-3alpha,17beta-diols, 5alpha/beta-pregnan-3alpha-ol-20-ones and lithocholic acid). The reactivity towards all-trans-retinal of AKR1B19 is low
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additional information
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catalyzes the conversion of 3-keto-saturated steroids such as 5alpha-dihydrotestosterone, DHT, and 5alpha-androstane-3,17-dione, A-dione, into less active steroids
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?
additional information
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sterol substrate specificity with 4alpha-monomethyl- and 4,4-dimethyl-3-ketosteroids
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additional information
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catalyzes NADPH-dependent reduction of 3-ketosteroid intermediates, 4-methyl sterol intermediates, of cholesterol biosynthesis from lanosterol, regenerates 3beta-hydroxy sterol
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additional information
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enzyme of mevalonate pathway for biosynthesis of cholesterol from lanosterol
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?
additional information
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involved in the 10-step oxidative removal of the 4-gem-dimethyl group of sterols
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additional information
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step of biosynthesis of hormonal steroids
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additional information
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the enzyme is also involved in synthesis of estradiol and estrone, neurosteroids paly a role in brain develkopment and in stimulation and control of song function
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?
additional information
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3-keto reducing enzyme is specific for a 5alpha, trans A/B ring junction in the sterone substrate, as found in all sterol biosynthesis intermediates
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?
additional information
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4alpha-methyl-9beta,19-cyclo-C30-sterones and 4-desmethyl-DELTA7-C27-sterones or C30-sterones are preferentially reduced, 4,4-dimethyl-C30-sterones or C31-sterones react poorly. Produces stereoselectively corresponding 3beta-alcohol derivatives, no 3alpha-alcohol product is formed
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additional information
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catalyzes NADPH-dependent C-3 reduction of various sterones to produce stereoselectively the corresponding 3beta-hydroxy derivatives
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constitutive component of microsomal sterol 4-demethylation complex in photosynthetic organism
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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
(4-methyl)zymosterone + NADPH + H+
(4-methyl)zymosterol + NADP+
cholesterol pathway
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?
2 17beta-hydroxy-5alpha-androstan-3-one + 2 NADPH + 2 H+
5alpha-androstane-3beta,17beta-diol + 5alpha-androstane-3alpha,17beta-diol + 2 NADP+
AKR1cs are a source of beta-tetrahydrosteroids. This is of physiological significance because the formation of 3beta-diol in contrast to 3alpha-diol is virtually irreversible, the 3beta-diol is a pro-apoptotic ligand for estrogen receptor beta, and 3beta-tetrahydrosteroids act as gamma-aminobutyric acid type A receptor antagonists
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?
5alpha-dihydrotestosterone + NADPH + H+
5alpha-androstan-3alpha,17beta-diol + NADP+
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in prostate cells AKR1C2 acts as a 3-ketosteroid reductase to eliminate 5alpha-dihydrotestosterone and prevents activation of androgen receptor. AKR1C2 does not act as an oxidase due to either potent product inhibition by NADPH or because it cannot surmount the oxidative 17beta-hydroxysteroid dehydrogenase present. AKR1C2 is not a source of 5alpha-dihydrotestosterone in PC-3 cells
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?
dihydrotestosterone + NADPH + H+
5alpha-androstane-3beta,17beta-diol + NADP+
steroid hormone pathway
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?
progesterone + NADPH + H+
4-pregnen-3beta-ol-20-one + NADP+
steroid hormone pathway
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?
additional information
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enzyme of sterol, ergosterol, biosynthesis, enzyme catalyzes last step in demethylation at C-4
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?
additional information
?
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HSD17B7 participates in postsqualene cholesterol biosynthesis, HSD17B7 is a novel candidate for inborn errors of cholesterol metabolism
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?
additional information
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tibolone is used to treat climacteric symptoms and prevent osteoporosis, it exerts tissue-selective effects via site-specific metabolism into 3alpha- and 3beta-hydroxymetabolites and a DELTA4-isomer, In Hep-G2 cell cytosol and intact cells tibolone is exclusively reduced to 3beta-hydroxytibolone, tibolone metabolism in human liver is catalyzed by 3alpha/3beta-hydroxysteroid dehydrogenase activities of the four isoforms of the aldo-keto reductase (AKR)1C subfamily, overview
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?
additional information
?
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enzyme might form complexes with other proteins, including possibly DNA-binding proteins, under low ionic strength conditions
-
-
?
additional information
?
-
-
HSD17B7 participates in postsqualene cholesterol biosynthesis
-
-
?
additional information
?
-
-
the enzyme, termed AKR1B19, acts not only as a reductase for reactive carbonyl compounds derived from lipid peroxidation like AR-like proteins of other species, but also as a superior reductive 3beta-HSD for 3-keto-5alpha/beta-dihydro-C19/C21/C24-steroids
-
-
?
additional information
?
-
-
catalyzes the conversion of 3-keto-saturated steroids such as 5alpha-dihydrotestosterone, DHT, and 5alpha-androstane-3,17-dione, A-dione, into less active steroids
-
-
?
additional information
?
-
-
catalyzes NADPH-dependent reduction of 3-ketosteroid intermediates, 4-methyl sterol intermediates, of cholesterol biosynthesis from lanosterol, regenerates 3beta-hydroxy sterol
-
-
?
additional information
?
-
-
enzyme of mevalonate pathway for biosynthesis of cholesterol from lanosterol
-
-
?
additional information
?
-
-
involved in the 10-step oxidative removal of the 4-gem-dimethyl group of sterols
-
-
?
additional information
?
-
-
step of biosynthesis of hormonal steroids
-
-
?
additional information