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Literature summary for 1.14.15.6 extracted from

  • Sheets, J.J.; Vickery, L.E.
    C-22-Substituted steroid derivatives as substrate analogues and inhibitors of cytochrome P-450scc (1983), J. Biol. Chem., 258, 1720-1725.
    View publication on PubMed
Search for more literature for 1.14.15.6

Inhibitors

Inhibitors Comment Organism Structure
22-Amino-23,24-bisnor-5-cholen-3beta-ol 22-amine derivative, same steroid ring structure as cholesterol, competitive inhibitor with respect to cholesterol, 50% reversible inhibition at 0.0001 mM, reversible cooperative binding; dual interaction: binding of steroid ring to cholesterol site and bonding of the amine to the heme iron. need not be metabolically activated in order to inhibit the enzyme, not metobolized to pregnenolone. 60% competitive inhibition at 0.00015 mM Bos taurus
22-amino-23,24-bisnor-5alpha-cholen-3beta-ol 50% inhibition at 0.003 mM Bos taurus
23,24-bisnor-5-cholene-3beta,22-diol competitive inhibitor, 40% inhibition at 0.01 mM, 50% at 0.015 mM, resembles the intermediate 22-hydroxycholesterol but acts as an inhibitor rather than serving as a substrate Bos taurus
additional information amine binding to heme is important for tight inhibitor potency rather than the 5-androstene ring, 23,24-bisnor-5-cholen-3beta-ol-22-carboxamide is ineffective as inhibitor, side chain carbons 23-27 may play some role in positioning the substrate for hydroxylation; cholesterol analogues have shortened side chain and primary amine group, tested in presence of 0.07 mM cholesterol Bos taurus

Localization

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

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
cholesterol + 6 reduced adrenodoxin + 3 O2 Bos taurus
-
 pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O
-
 ?

Organism

Organism UniProt Comment Textmining
Bos taurus
-
-
-

Purification (Commentary)

Purification (Comment) Organism
-
 Bos taurus

Source Tissue

Source Tissue Comment Organism Textmining
adrenal cortex
-
 Bos taurus
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
cholesterol + 6 reduced adrenodoxin + 3 O2
-
 Bos taurus pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O
-
 ?
cholesterol + reduced adrenodoxin + O2 intermediates (22R)-22-hydroxycholesterol and (20R,22R)-20,22-dihydroxycholesterol from hydroxylation Bos taurus pregnenolone + 4-methylpentanal + oxidized adrenodoxin + H2O
-
 ?
cholesterol + reduced adrenodoxin + O2 hydroxylation of cholesterol at C-22, then C-20, followed by oxidative scission of the glycol to get pregnenolone Bos taurus pregnenolone + 4-methylpentanal + oxidized adrenodoxin + H2O
-
 ?
additional information only a single active site of enzyme Bos taurus ?
-
 ?

Subunits

Subunits Comment Organism
? single band, SDS-PAGE Bos taurus

Temperature Optimum [°C]

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

pH Optimum

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

Cofactor

Cofactor Comment Organism Structure
adrenodoxin promotes cholesterol binding Bos taurus
heme 3 mixed function oxidation cycles at the single heme center Bos taurus
NADPH
-
 Bos taurus