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Literature summary extracted from

  • Paik, Y.K.; Trzaskos, J.M.; Shafiee, A.; Gaylor, J.L.
    Microsomal enzymes of cholesterol biosynthesis from lanosterol. Characterization, solubilization, and partial purification of NADPH-dependent DELTA8,14-steroid 14-reductase (1984), J. Biol. Chem., 259, 13413-13423.
    View publication on PubMed

Activating Compound

EC Number Activating Compound Comment Organism Structure
1.3.1.70 phosphatidylcholine liposomal phosphatidylcholine, egg yolk: 1.4fold activation Rattus norvegicus
1.3.1.70 Phospholipids partially purified enzyme: activation Rattus norvegicus

Application

EC Number Application Comment Organism
1.3.1.70 analysis partial purified enzyme suitable for reconstitution studies, reconstitution of isolated, soluble enzymes involved in cholesterol biosynthesis from lanosterol Rattus norvegicus

General Stability

EC Number General Stability Organism
1.3.1.70 detergents such as Lubrol-WX, Emulgen 911, Triton X-100, Triton WR-1339, and their combinations with ionic detergents such as taurodeoxycholate, cholate, and Na+ salts destroy enzyme even at low concentration, 0.1-0.5%, w/v Rattus norvegicus
1.3.1.70 enzyme in soluble form is very instable Rattus norvegicus
1.3.1.70 stable against trypsin treatment Rattus norvegicus

Inhibitors

EC Number Inhibitors Comment Organism Structure
1.3.1.70 Ca2+ 4 mM: very slight, 3.5% inhibition Rattus norvegicus
1.3.1.70 cyanide cyanide ion, membrane-bound enzyme, modest inhibition at high concentrations, greater than 1 mM, partial purified enzyme, sodium cyanide, no or very poor inhibition, 10 mM: 3.5% inhibition Rattus norvegicus
1.3.1.70 HgCl2 3 mM: more than 99% inhibition, inhibition negligible in the presence of 10 mM glutathione Rattus norvegicus
1.3.1.70 Mg2+ 4 mM: slight, 6% inhibition Rattus norvegicus
1.3.1.70 additional information no direct inhibition by 3beta-hydroxy-4,4-dimethyl-5alpha-cholest-8(14)-en-15-one, even when concentration is increased to level of Km for substrate; no inhibition by trypsin Rattus norvegicus
1.3.1.70 N-ethylmaleimide 5 mM: 53% inhibition, inhibition negligible in the presence of 10 mM glutathione Rattus norvegicus
1.3.1.70 O2 28% inhibition Rattus norvegicus
1.3.1.70 Phospholipase A2 very high inhibition by very small concentrations, activity not restored by addition of phospholipids or any components presumed to be released from treated microsomes. Various concentration ranges of potential cofactors including FMN, FAD, AMP, ADP, ATP, coenzyme Q, Coenzyme A, and hemin, plus heat-treated microsomes, and lipid extracts of microsomes does not restore microsomal 14-reductase of phospholipase A2-treated microsomes Rattus norvegicus
1.3.1.70 sulfhydryl-binding agents
-
Rattus norvegicus
1.3.1.70 trans-1,4-bis(2-chlorobenzylaminomethyl)cyclohexane dihydrochloride AY-9944, strong inhibition, 0.0003 mM: 50% inhibition, 0.0005 mM: 65% inhibition Rattus norvegicus
1.3.1.70 Triparanol 4-chloro-alpha-[4-[2-diethylaminoethoxy]phenyl]-alpha-(4-methylphenyl)benze-methanol, slight inhibition Rattus norvegicus
1.3.1.70 Tris-HCl Tris-HCl buffer, 28% inhibition, not restored by addition of KCl at various concentrations Rattus norvegicus

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
1.3.1.70 additional information
-
additional information kinetics Rattus norvegicus
1.3.1.70 additional information
-
additional information kinetic data Rattus norvegicus
1.3.1.70 0.0294
-
4,4-dimethyl-5alpha-cholesta-7,14-dien-3beta-ol membrane-bound enzyme, Lineweaver-Burk Rattus norvegicus
1.3.1.70 0.0333
-
4,4-dimethyl-5alpha-cholesta-7,14-dien-3beta-ol soluble enzyme Rattus norvegicus
1.3.1.70 0.0345
-
4,4-dimethyl-5alpha-cholesta-7,14-dien-3beta-ol microsomal-bound enzyme Rattus norvegicus
1.3.1.70 0.6
-
NADPH membrane-bound enzyme Rattus norvegicus

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining
1.3.1.70 endoplasmic reticulum
-
Rattus norvegicus 5783
-
1.3.1.70 membrane membrane-bound Rattus norvegicus 16020
-
1.3.1.70 microsome microsomal-bound Rattus norvegicus
-
-
1.3.1.70 additional information distribution Rattus norvegicus
-
-

Metals/Ions

EC Number Metals/Ions Comment Organism Structure
1.3.1.70 additional information no activation by Mg2+ or Ca2+, 0.5-20 mM, but slight inhibition Rattus norvegicus

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
1.3.1.70 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol + NADPH Rattus norvegicus presumably the natural substrate 4,4-dimethyl-5alpha-cholesta-8-en-3beta-ol + NADP+
-
?
1.3.1.70 additional information Rattus norvegicus catalyzes anaerobically NADPH-dependent reduction of 14-double bond of 8,14-diene or 7,14-diene sterols that are sterol intermediates formed during C-32 demethylation in cholesterol biosynthesis from lanosterol in mammals ?
-
?
1.3.1.70 additional information Rattus norvegicus reduction of 14-double bond of sterol-conjugated dienes ?
-
?
1.3.1.70 additional information Rattus norvegicus microsomal enzyme of cholesterol biosynthesis from lanosterol ?
-
?

Organism

EC Number Organism UniProt Comment Textmining
1.3.1.70 Rattus norvegicus
-
male sprague-dawley rats
-

Purification (Commentary)

EC Number Purification (Comment) Organism
1.3.1.70 solubilization with combined octylglucoside and sodium taurodeoxycholate system and partial purification Rattus norvegicus

Reaction

EC Number Reaction Comment Organism Reaction ID
1.3.1.70 4,4-dimethyl-5alpha-cholesta-8,24-dien-3beta-ol + NADP+ = 4,4-dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol + NADPH + H+ reduction of 14-double bond of conjugated DELTA8,14-sterols and DELTA7,14-sterols Rattus norvegicus

Source Tissue

EC Number Source Tissue Comment Organism Textmining
1.3.1.70 liver
-
Rattus norvegicus
-

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
1.3.1.70 0.0555
-
partially purified enzyme Rattus norvegicus

Storage Stability

EC Number Storage Stability Organism
1.3.1.70 -80°C, 1 week, stable Rattus norvegicus
1.3.1.70 4°C, overnight, 30% activity lost Rattus norvegicus

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.3.1.70 4,4-dimethyl-5alpha-cholesta-7,14-dien-3beta-ol + NADPH 64% activity compared with 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol Rattus norvegicus 4,4-dimethyl-5alpha-cholesta-7-en-3beta-ol + NADP+
-
?
1.3.1.70 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol + NADPH best substrate, probably natural substrate Rattus norvegicus 4,4-dimethyl-5alpha-cholesta-8-en-3beta-ol + NADP+
-
?
1.3.1.70 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol + NADPH presumably the natural substrate Rattus norvegicus 4,4-dimethyl-5alpha-cholesta-8-en-3beta-ol + NADP+
-
?
1.3.1.70 5alpha-cholesta-7,14-dien-3beta-ol + NADPH 43% activity compared with 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol Rattus norvegicus 5alpha-cholesta-7-en-3beta-ol + NADP+
-
?
1.3.1.70 5alpha-cholesta-8,14-dien-3beta-ol + NADPH DELTA8,14-cholestadien-3beta-ol Rattus norvegicus 5alpha-cholesta-8-en-3beta-ol + NADP+
-
?
1.3.1.70 5alpha-cholesta-8,14-dien-3beta-ol + NADPH 53% activity compared with 4,4-dimethyl-5alpha-cholesta-8,14-dien-3beta-ol Rattus norvegicus 5alpha-cholesta-8-en-3beta-ol + NADP+
-
?
1.3.1.70 additional information substrate specificity Rattus norvegicus ?
-
?
1.3.1.70 additional information enzyme acts on a range of steroids with a 14(15)-double bond Rattus norvegicus ?
-
?
1.3.1.70 additional information reduction of 14-double bond of conjugated DELTA8,14-diene sterols and DELTA7,14-diene sterols Rattus norvegicus ?
-
?
1.3.1.70 additional information sterol substrate specificity study Rattus norvegicus ?
-
?
1.3.1.70 additional information anaerobic conditions yield maximal rates of reduction Rattus norvegicus ?
-
?
1.3.1.70 additional information 4-nor-methyldiene sterols, 5alpha-cholesta-8,14-dien-3beta-ol, and 5alpha-cholesta-7,14-dien-3beta-ol are reduced at about 50% of the rate of the corresponding 4-gem-dimethyldiene sterols, for both the C27-sterol and C29-sterol, the higher reaction rate of the 8,14-diene system is consistently observed over the isomeric 7,14-diene Rattus norvegicus ?
-
?
1.3.1.70 additional information catalyzes anaerobically NADPH-dependent reduction of 14-double bond of 8,14-diene or 7,14-diene sterols that are sterol intermediates formed during C-32 demethylation in cholesterol biosynthesis from lanosterol in mammals Rattus norvegicus ?
-
?
1.3.1.70 additional information reduction of 14-double bond of sterol-conjugated dienes Rattus norvegicus ?
-
?
1.3.1.70 additional information microsomal enzyme of cholesterol biosynthesis from lanosterol Rattus norvegicus ?
-
?

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
1.3.1.70 37
-
assay at, anaerobically Rattus norvegicus

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
1.3.1.70 7.4
-
pH-optimum and assay at, anaerobically Rattus norvegicus

pH Range

EC Number pH Minimum pH Maximum Comment Organism
1.3.1.70 additional information
-
14-reductase has relatively broad pH profile in acidic region, activity drastically decreases with only moderate elevation of pH above 7.8 Rattus norvegicus
1.3.1.70 7.8
-
14-reductase has relatively broad pH profile in acidic region, activity drastically decreases with only moderate elevation of pH above 7.8 Rattus norvegicus

Cofactor

EC Number Cofactor Comment Organism Structure
1.3.1.70 additional information NADH only poorly supports reduction Rattus norvegicus
1.3.1.70 NADPH NADPH-dependent Rattus norvegicus
1.3.1.70 NADPH NADPH required, NADH has 4.5%, of the NADPH activity Rattus norvegicus