FADS3
Description
The FADS3 (fatty acid desaturase 3) is a protein-coding gene located on chromosome 11.
FADS3 is a human gene that encodes an enzyme called fatty acid desaturase 3 (FADS3). This enzyme is involved in the synthesis of sphingolipids, which are important components of cell membranes. FADS3 introduces a cis double bond between carbon 14 and carbon 15 of the sphingoid base, producing LCBs such as sphinga-4,14-dienine (SPD, d18:2(4E,14Z)) from SPH. FADS3 also acts as a methyl-end fatty acyl coenzyme A (CoA) desaturase that introduces a cis double bond between the preexisting double bond and the terminal methyl group of the fatty acyl chain. It desaturates (11E)-octadecenoate (trans-vaccenoate, the predominant trans fatty acid in human milk) at carbon 13 to generate (11E,13Z)-octadecadienoate (also known as conjugated linoleic acid 11E,13Z-CLA).
FADS3 is an enzyme that introduces a cis double bond between carbon 14 and carbon 15 of the sphingoid base (also known as long chain base, LCB), producing LCBs such as sphinga-4,14-dienine (SPD, d18:2(4E,14Z)) from SPH. It prefers SPH-containing ceramides (N-acylsphing-4-enines) as substrates and is capable of metabolizing the SPH in its free form. SPD ceramides occur widely in mammalian tissues and cells. Due to their unusual structure containing a cis double bond, SPD ceramides may have an opposite, negative role in lipid microdomain formation relative to conventional ceramides. FADS3 may be involved in the detoxification of 1-deoxy sphingolipids, by desaturating the cytotoxic 1-deoxysphinganine (1-deoxySA, m18:0), produced under pathological conditions, to 1-deoxysphingenine (1-deoxysphingosine, 1-deoxySO, m18:1). Although it prefers SPH-containing ceramides (N-acylsphing-4-enines) as substrates, FADS3 also exhibits activity toward dihydrosphingosine-containing CERs (N-acylsphinganines) and produces 14Z-SPH-containing sphingolipids, which can be found in patients with DEGS1 mutations. Its desaturase mechanism involves an electron transfer facilitated by cytochrome b5. FADS3 also acts as a methyl-end fatty acyl coenzyme A (CoA) desaturase that introduces a cis double bond between the preexisting double bond and the terminal methyl group of the fatty acyl chain. It desaturates (11E)-octadecenoate (trans-vaccenoate, the predominant trans fatty acid in human milk) at carbon 13 to generate (11E,13Z)-octadecadienoate (also known as conjugated linoleic acid 11E,13Z-CLA).
FADS3 is also known as CYB5RP, LLCDL3.
