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Literature summary for 1.14.15.6 extracted from

  • Hanukoglu, I.; Privalle, C.T.; Jefcoate, C.R.
    Mechanisms of ionic activation of adrenal mitochondrial cytochromes P-450scc and P-45011beta (1981), J. Biol. Chem., 256, 4329-4335.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
Phospholipid inclusion of P-450 into vesicles Bos taurus

Inhibitors

Inhibitors Comment Organism Structure
adrenodoxin oxidized form, high affinity to P-450scc, inhibits side chain cleavage by competition with reduced form Bos taurus
Ca2+ CaCl2 inhibits side chain cleavage activity at 100 mM NaCl, 50% inhibition with 0.07 mM in Tween 20 and 0.03 mM for vesicle-incorporated, Ca2+ does not affect binding of either cholesterol of oxidized adrenodoxin to P-450scc Bos taurus

Localization

Localization Comment Organism GeneOntology No. Textmining
mitochondrial inner membrane adrenodoxin reductase and adrenodoxin are peripheral proteins on matrix side of inner membrane, P-450scc is integral membrane protein Bos taurus 5743
-
mitochondrial inner membrane integral to membrane Bos taurus 5743
-

Metals/Ions

Metals/Ions Comment Organism Structure
Ca2+ ineffective activator Bos taurus
Ca2+ particulary but also other metal ions modulate adrenodoxin binding to adrenodoxin reductase and P-450, therefore activation of cholesterol side chain cleavage and adrenodoxin reduction Bos taurus
Mg2+ increased MgCl2 concentrations continue to increase side chain cleavage activity even after all adrenodoxin is reduced Bos taurus
additional information increase of side chain cleavage activity from 50 to 100 mM NaCl, higher concentrations cause a decrease, total loss at 300 mM Bos taurus

Organism

Organism UniProt Comment Textmining
Bos taurus
-
-
-

Purification (Commentary)

Purification (Comment) Organism
DEAE-cellulose, adrenodoxin-Sepharose 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 + reduced adrenodoxin + O2
-
Bos taurus pregnenolone + 4-methylpentanal + oxidized adrenodoxin + H2O
-
?
additional information cholesterol side chain cleavage activity is dependent on free reduced adrenodoxin Bos taurus ?
-
?
additional information suggested shuttle mechanism in which adrenodoxin transfers electrons between adrenodoxin reductase and cytochrome P-450. No ternary adrenodoxin-adrenodoxin reductase-P-450 complex Bos taurus ?
-
?
additional information dissociation of oxidized adrenodoxin from P-450scc must be a potential rate-limiting factor 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 transports electrons from adrenodoxin reductase to cytochrome P-450 by shuttling Bos taurus
NADPH NADPH-linked adrenodoxin reductase Bos taurus