EC Explorer
[browse EC tree] - [search]
EC 1.14.15.6 Details
show Brenda entryEC number
1.14.15.6
Accepted name
cholesterol monooxygenase (side-chain-cleaving)
Reaction
cholesterol + 6 reduced adrenodoxin + 3 O2 + 6 H+ = pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O (overall reaction);;(1a) cholesterol + 2 reduced adrenodoxin + O2 + 2 H+ = (22R)-22-hydroxycholesterol + 2 oxidized adrenodoxin + H2O;;(1b) (22R)-22-hydroxycholesterol + 2 reduced adrenodoxin + O2 + 2 H+ = (20R,22R)-20,22-dihydroxycholesterol + 2 oxidized adrenodoxin + H2O;;(1c) (20R,22R)-20,22-dihydroxy-cholesterol + 2 reduced adrenodoxin + O2 + 2 H+ = pregnenolone + 4-methylpentanal + 2 oxidized adrenodoxin + 2 H2O
Other name(s)
cholesterol desmolase,
cytochrome P-450scc,
C27-side chain cleavage enzyme,
cholesterol 20-22-desmolase,
cholesterol C20-22 desmolase,
cholesterol side-chain cleavage enzyme,
cholesterol side-chain-cleaving enzyme,
steroid 20-22 desmolase,
steroid 20-22-lyase,
CYP11A1 (gene name)
Systematic name
cholesterol,reduced-adrenodoxin:oxygen oxidoreductase (side-chain-cleaving)
CAS registry number
37292-81-2, 440354-98-3
Comment
A heme-thiolate protein (cytochrome P-450). The reaction proceeds in three stages, with two hydroxylations at C-22 and C-20 preceding scission of the side-chain between carbons 20 and 22. The initial source of the electrons is NADPH, which transfers the electrons to the adrenodoxin via EC 1.18.1.6, adrenodoxin-NADP+ reductase.
History
created 1983, modified 2013, modified 2014
back to topEC Tree
1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
1.14.15.1 camphor 5-monooxygenase
