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Literature summary extracted from

  • Miao, E.; Joardar, S.; Zuo, C.; Cloutier, N.J.; Nagahisa, A.; Byon, C.; Wilson, S.R.; Orme-Johnson, W.H.
    Cytochrome P-450scc-mediated oxidation of (20S)-22-thiacholesterol: Characterization of mechanism-based inhibition (1995), Biochemistry, 34, 8415-8421.
    View publication on PubMed

Application

EC Number Application Comment Organism
1.14.15.6 medicine treatment of certain hormone-related pathologies Bos taurus

Inhibitors

EC Number Inhibitors Comment Organism Structure
1.14.15.6 (20S)-22-thiacholesterol competitive inhibitor, is converted enzymatically to a more potent inhibitor, the (22S) and (22R) sulfoxides, inhibition by approximately 75% at 0.001 mM, no inactivation in absence of NADPH and O2 Bos taurus
1.14.15.6 (20S,22R)-22-thiacholesterol S-oxide competitive versus cholesterol, binds 10times more tightly than (22S) diastereomer, 25% and 44% inhibition at 0.00005 mM and 0.0001 mM, respectively, complete inhibition at 0.001 mM, no substrate for P-450 Bos taurus
1.14.15.6 (20S,22S)-22-thiacholesterol S-oxide competitive versus cholesterol, no substrate for P-450 Bos taurus
1.14.15.6 additional information mechanism-based inhibition, no inhibition with (20R)-22-thiacholesterol at 0.001 mM, inhibition by occupying the cholesterol binding pocket Bos taurus

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining
1.14.15.6 mitochondrial inner membrane
-
 Bos taurus 5743
-

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
1.14.15.6 cholesterol + 6 reduced adrenodoxin + 3 O2 Bos taurus first step in biosynthesis of all steroid hormones pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O isocapraldehyde additional product ?

Organism

EC Number Organism UniProt Comment Textmining
1.14.15.6 Bos taurus
-
-
-

Purification (Commentary)

EC Number Purification (Comment) Organism
1.14.15.6
-
 Bos taurus

Source Tissue

EC Number Source Tissue Comment Organism Textmining
1.14.15.6 adrenal cortex
-
 Bos taurus
-

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.14.15.6 (20S)-22-thiacholesterol + reduced adrenodoxin + O2
-
 Bos taurus (20S,22R)-22-thiacholesterol S-oxide + (20S,22S)-22-thiacholesterol S-oxide (22R)-sulfoxide preferentially formed by a factor of 4.2 to 1 over (22S)-sulfoxide ?
1.14.15.6 cholesterol + 6 reduced adrenodoxin + 3 O2 first step in biosynthesis of all steroid hormones Bos taurus pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O isocapraldehyde additional product ?
1.14.15.6 cholesterol + reduced adrenodoxin + O2
-
 Bos taurus pregnenolone + 4-methylpentanal + oxidized adrenodoxin + H2O
-
 ?
1.14.15.6 additional information 3 high regioselective and stereospecific oxidation steps at the same heme active site Bos taurus ?
-
 ?

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
1.14.15.6 37
-
 assay at Bos taurus

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.14.15.6 0.05
-
 cholesterol
-
 Bos taurus

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
1.14.15.6 7.2
-
 assay at Bos taurus

Cofactor

EC Number Cofactor Comment Organism Structure
1.14.15.6 adrenodoxin
-
 Bos taurus
1.14.15.6 heme
-
 Bos taurus
1.14.15.6 NADPH NADPH-linked adrenodoxin reductase Bos taurus