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Literature summary for 1.1.1.270 extracted from

  • Pascal, S.; Taton, M.; Rahier, A.
    Plant sterol biosynthesis: identification of a NADPH dependent sterone reductase involved in sterol-4 demethylation (1994), Arch. Biochem. Biophys., 312, 260-271.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
additional information no activation by 1 mM hydrogen peroxide Zea mays

Inhibitors

Inhibitors Comment Organism Structure
itraconazole no inhibition Zea mays
additional information no inhibition by azole inhibitors, 1 mM, pyrifenox, ketoconazole, and itraconazole, no inhibition by phenobarbital and pyrazole. No inhibition by 1 mM cyanide or 1 mM hydrogen peroxide, insensitive to carbon monooxide Zea mays

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.003
-
NADPH substrate: DELTA7-chondrillastenone Zea mays
0.004
-
NADPH substrate: cycloeucalenone Zea mays
0.067
-
cycloartenone
-
Zea mays
0.085
-
24-methylenecycloartanone
-
Zea mays
0.1
-
cyclolaudenone
-
Zea mays
0.162
-
24-methylenelophenone
-
Zea mays
0.22
-
cholestanone
-
Zea mays
0.22
-
cycloeucalenone
-
Zea mays
0.245
-
DELTA7-chondrillastenone
-
Zea mays
0.26
-
obtusifolione
-
Zea mays
0.42
-
DELTA7-cholestenone
-
Zea mays

Localization

Localization Comment Organism GeneOntology No. Textmining
membrane
-
Zea mays 16020
-
microsome
-
Zea mays
-
-

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
additional information Zea mays constitutive component of microsomal sterol 4-demethylation complex in photosynthetic organism ?
-
?
additional information Zea mays enzyme of plant sterol biosynthesis, involved in sterol-4 demethylation, invoves the removal of two methyl groups at C4 ?
-
?

Organism

Organism UniProt Comment Textmining
Zea mays
-
maize, variety LG11
-

Reaction

Reaction Comment Organism Reaction ID
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> Zea mays

Source Tissue

Source Tissue Comment Organism Textmining
embryo
-
Zea mays
-
seedling
-
Zea mays
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
24-ethylidenelophenone + NADPH oxidation: poor Zea mays 24-ethylidenelophenol + NADP+
-
r
24-methylenecycloartanone + NADPH 7% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays 24-methylenecycloartanol + NADP+
-
ir
24-methylenelophenone + NADPH 35% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays 24-methylenelophenol + NADP+
-
?
24-methylenepollinastanone + NADPH + acetate 70% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays 24-methylenepollinastanol + NADP+
-
?
24RS-dihydrocycloeucalenone + NADPH 53% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays 24RS-dihydrocycloeucalenol + NADP+
-
?
4beta-methyl-28-nor-24RS-dihydrocycloeucalenone + NADPH 27% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays 4beta-methyl-28-nor-24RS-dihydrocycloeucalenol + NADP+
-
?
avenastenone + NADPH more than 72% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays avenasterol + NADP+
-
?
cholest-7-en-3-one + NADPH DELTA7-cholestenone, best substrate Zea mays 3beta-hydroxy-cholest-7-ene + NADP+ DELTA7-cholesterol ir
cholestanone + NADPH 57% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays cholestanol + NADP+
-
?
cycloartenone + NADPH 7% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays cycloartenol + NADP+
-
ir
cycloeucalenone + NADPH + H+ putative endogenous substrate for sterone reductase Zea mays cycloeucalenol + NADP+ reverse oxidation: about 35% of forward reductase rate r
cycloeucalenone + NADPH + H+ putative endogenous substrate for sterone reductase Zea mays cycloeucalenol + NADP+ 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+ 68% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays cycloeucalenol + NADP+ reverse oxidation: about 35% of forward reductase rate r
cycloeucalenone + NADPH + H+ 68% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays cycloeucalenol + NADP+ 17-(4-isopropyl-1-methyl-pent-4-enyl)-4,13,14-trimethyl-tetradecahydro-cyclopropa[9,10]cyclopenta[a]phenanthren-3beta-ol r
cyclolaudenone + NADPH 10% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays cyclolaudenol + NADP+
-
?
DELTA7-chondrillastenone + NADPH 70% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays DELTA7-chondrillasterol + NADP+ 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 5alpha,28beta(H)-stigmasta-7,22-dien-3-one Zea mays DELTA7-chondrillasterol + NADP+ 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 ?
additional information substrate specificity Zea mays ?
-
?
additional information coprostanol: not a substrate Zea mays ?
-
?
additional information 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 Zea mays ?
-
?
additional information 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 Zea mays ?
-
?
additional information catalyzes NADPH-dependent C-3 reduction of various sterones to produce stereoselectively the corresponding 3beta-hydroxy derivatives Zea mays ?
-
?
additional information constitutive component of microsomal sterol 4-demethylation complex in photosynthetic organism Zea mays ?
-
?
additional information enzyme of plant sterol biosynthesis, involved in sterol-4 demethylation, invoves the removal of two methyl groups at C4 Zea mays ?
-
?
obtusifolione + NADPH 43% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays obtusifoliol + NADP+ 4,14-dimethyl-ergosta-8,24(28)-dien-3-ol ?
obtusifolione + NADPH 4,14-dimethyl-ergosta-8,24(28)-dien-3-one Zea mays obtusifoliol + NADP+ 4,14-dimethyl-ergosta-8,24(28)-dien-3-ol ?
spinastenone + NADPH 32% compared with cholest-7-en-3-one, DELTA7-cholestenone Zea mays spinasterol + NADP+
-
?

Cofactor

Cofactor Comment Organism Structure
additional information essentially inactive with NADH Zea mays
NADP+ oxidation, poorly, only few substrates Zea mays
NADPH specific for NADPH, NADH is essentially inactive, less than 10% Zea mays