CYP11A1 cleaves 20a,22b-DHCHOL

Stable Identifier
Reaction [transition]
Homo sapiens
20alpha,22beta-hydroxycholesterol is cleaved by CYP11A1 to yield pregnenolone and isocaproaldehyde, 20alpha,22beta-hydroxycholesterol + NADPH + H+ + O2 => pregnenolone + isocaproaldehyde + NADP+ + H2O
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20alpha,22beta-hydroxycholesterol (20a,22b-DHCHOL), NADPH + H+, and O2 react to form pregnenolone (PREG), isocaproaldehyde (ISCAL), NADP+ and H2O. This cleavage reaction is catalysed by CYP11A (P450scc) associated with the inner mitochondrial membrane (Strushkevich et al. 2011). PREG is substantially more hydrophilic than cholesterol (CHOL) and hydroxycholesterol (HCHOL) and is released into the mitochondrial matrix.

Literature References
PubMed ID Title Journal Year
3024157 Human cholesterol side-chain cleavage enzyme, P450scc: cDNA cloning, assignment of the gene to chromosome 15, and expression in the placenta

Miller, WL, Chung, BC, Voutilainen, R, Mohandas, TK, Matteson, KJ

Proc Natl Acad Sci U S A 1986
21636783 Structural basis for pregnenolone biosynthesis by the mitochondrial monooxygenase system

Park, HW, Grabovec, I, Usanov, S, MacKenzie, F, Cherkesova, T, Strushkevich, N

Proc. Natl. Acad. Sci. U.S.A. 2011
9578606 Expression of catalytically active human cytochrome p450scc in Escherichia coli and mutagenesis of isoleucine-462

Downs, T, Tuckey, RC, Woods, ST, Triantopoulos, T, Sadleir, J, Headlam, MJ

Arch Biochem Biophys 1998
Catalyst Activity

cholesterol monooxygenase (side-chain-cleaving) activity of CYP11A1:FDXR:FDX1,FDX1L (red.) [mitochondrial matrix]

Orthologous Events
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