CYP11A1
CYP11A1 (cytochrome P450 family 11 subfamily A member 1, also known as P450SCC or CYP11A) is a mitochondrial cytochrome P450 monooxygenase. It converts cholesterol to pregnenolone, the precursor of most steroid hormones. Browse Assay Genie's current range of CYP11A1 research reagents below, or read on for the biology behind the target.
CYP11A1 is the cholesterol side-chain cleavage enzyme. It catalyses the side-chain hydroxylation and cleavage of cholesterol to pregnenolone through three sequential oxidation reactions: hydroxylation at C22, then at C20 to give 20R,22R-hydroxycholesterol, and finally cleavage between C20 and C22. The products are the C21-steroid pregnenolone and 4-methylpentanal. Mechanistically, the enzyme uses molecular oxygen, inserting one oxygen atom into the substrate and reducing the second to water. The two electrons required come from NADPH through a two-protein mitochondrial transfer system. This system comprises the flavoprotein FDXR (adrenodoxin/ferredoxin reductase) and the nonheme iron-sulfur protein FDX1 or FDX2 (adrenodoxin/ferredoxin).
The CYP11A1 gene encodes a member of the cytochrome P450 superfamily, a group of monooxygenases that act in drug metabolism and in the synthesis of cholesterol, steroids and other lipids. The protein localises to the mitochondrial inner membrane, where it carries out the first and rate-limiting step in steroid hormone synthesis. HGNC places it in the cytochrome P450 family 11 gene group, and the CYP11A1 protein is annotated as belonging to the cytochrome P450 family. Two transcript variants encoding different isoforms have been described. The cellular location of the smaller isoform is unclear because it lacks the mitochondrial-targeting transit peptide.
The gene has also been catalogued as cytochrome P450, subfamily XIA (cholesterol side chain cleavage), and the symbols P450SCC and CYP11A are older or alternative names. Orthologous genes, both named Cyp11a1, are found in mouse and rat, which allows the enzyme to be studied in rodent models of steroidogenesis.
CYP11A1 performs the first and rate-limiting conversion of cholesterol to pregnenolone, so it is a central reference point for studying steroidogenic pathways.
The enzyme sits in the inner mitochondrial membrane and depends on FDXR and FDX1 or FDX2 for electron transfer from NADPH.
CYP11A1 cleaves the cholesterol side chain through C22 and C20 hydroxylation, making it a model for sequential monooxygenase reactions on a lipid substrate.
As a member of the P450 superfamily, CYP11A1 is studied alongside other P450 enzymes involved in steroid and lipid synthesis.
CYP11A1 is a cytochrome P450 monooxygenase that converts cholesterol to pregnenolone, the precursor of most steroid hormones. It carries out hydroxylation at C22 and C20, then cleaves the bond between them. This is the first and rate-limiting step of steroid hormone synthesis.
CYP11A1 is also known as P450SCC and CYP11A, and its UniProt name is cholesterol side-chain cleavage enzyme, mitochondrial. Two transcript variants encode different isoforms. The smaller isoform lacks the mitochondrial-targeting transit peptide, so its cellular location is unclear.
Yes. Both mouse and rat have an ortholog named Cyp11a1, so the enzyme can be studied in rodent systems. Researchers should check the datasheet of any product for its validated reactivity before using it with a given species.
Other cytochrome P450 enzymes involved in steroid, sterol and lipid metabolism with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P05108; product specifications from Assay Genie datasheets.