CYP46A1

Description

The CYP46A1 (cytochrome P450 family 46 subfamily A member 1) is a protein-coding gene located on chromosome 14.

Cholesterol 24-hydroxylase (EC 1.14.13.98), also commonly known as cholesterol 24S-hydroxylase, cholesterol 24-monooxygenase, CYP46, or CYP46A1, is an enzyme that catalyzes the conversion of cholesterol to 24S-hydroxycholesterol. It is responsible for the majority of cholesterol turnover in the human central nervous system. The systematic name of this enzyme class is cholesterol,NADPH:oxygen oxidoreductase (24-hydroxylating). This enzyme is a member of the cytochrome P450 (CYP) superfamily of enzymes. Like many other CYP enzymes that act on cholesterol, cholesterol-24 hydroxylase is a monooxygenase that hydroxylates the side-chain of cholesterol. Because 24S-hydroxycholesterol is more polar than cholesterol, it can more easily pass the blood–brain barrier to exit the brain and pass into the bloodstream, where it can then travel to the liver to be further degraded. This enzyme has also been found at low quantities in the retina, where it performs the same function to a lesser degree. Genetic cloning of the encoding gene (CYP46A1) was first accomplished in 1999 and an extensive E. coli expression and purification system was later developed in 2003.

== Molecular structure == The enzymatic structure of the human cholesterol-24 hydroxylase was determined via crystallography at the Stanford Synchrotron Radiation Lightsource, and was shown to be a 57kDa (500 residue) monomeric heme-containing protein bound to the endoplasmic reticulum in neurons.

Cholesterol-24 hydroxylase is similar in structure to many other cytochrome P450s, possessing, for example, the conserved stretch of 23 hydrophobic residues in the N-terminus that make up a transmembrane-anchoring domain (residues 3-27).

P450 monooxygenase that plays a major role in cholesterol homeostasis in the brain. Primarily catalyzes the hydroxylation (with S stereochemistry) at C-24 of cholesterol side chain, triggering cholesterol diffusion out of neurons and its further degradation (PubMed:10377398, PubMed:14640697, PubMed:25017465, PubMed:18621681). By promoting constant cholesterol elimination in neurons, may activate the mevalonate pathway and coordinate the synthesis of new cholesterol and nonsterol isoprenoids involved in synaptic activity and learning (By similarity). Further hydroxylates cholesterol derivatives and hormone steroids on both the ring and side chain of these molecules, converting them into active oxysterols involved in lipid signaling and biosynthesis (PubMed:12077124, PubMed:14640697, PubMed:28190002). Acts as an epoxidase converting cholesta-5,24-dien-3beta-ol/desmosterol into (24S),25-epoxycholesterol, an abundant lipid ligand of nuclear NR1H2 and NR1H3 receptors shown to promote neurogenesis in developing brain (PubMed:25017465). May also catalyze the oxidative metabolism of xenobiotics, such as clotrimazole (PubMed:20667828). {ECO:0000250|UniProtKB:Q9WVK8, ECO:0000269|PubMed:10377398, ECO:0000269|PubMed:12077124, ECO:0000269|PubMed:14640697, ECO:0000269|PubMed:18621681, ECO:0000269|PubMed:20667828, ECO:0000269|PubMed:25017465, ECO:0000269|PubMed:28190002}

CYP46A1 is also known as CP46, CYP46.

Associated Diseases

WES Whole Exome Sequencing

Clinical Exome Sequencing