Stearoyl-CoA desaturase-1

Stearoyl-CoA desaturase (Δ-9-desaturase)
Stearoyl-CoA desaturase-1 bound to its substrate, Stearoyl-CoA (black). The catalytic centre iron ions (red) and water (blue) desaturate a bond in the tail of the substrate, which is held in a kinked conformation by the binding pocket. The enzyme is embedded in the membrane of the endoplasmic reticulum by four transmembrane helices. (PDB: 4ZYO​)
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 4ZYO
Identifiers
Symbols	SCD ; FADS5; MSTP008; SCD1; SCDOS
External IDs	OMIM: 604031 HomoloGene: 74538 ChEMBL: 5555 GeneCards: SCD Gene
EC number	1.14.19.1
Gene ontology Molecular function • stearoyl-CoA 9-desaturase activity • iron ion binding • oxidoreductase activity Cellular component • endoplasmic reticulum • endoplasmic reticulum membrane • membrane • integral component of membrane Biological process • unsaturated fatty acid biosynthetic process • oxidation-reduction process Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	6319	20249
Ensembl	ENSG00000099194	ENSMUSG00000037071
UniProt	O00767	P13516
RefSeq (mRNA)	NM_005063	NM_009127
RefSeq (protein)	NP_005054	NP_033153
Location (UCSC)	Chr 10: 100.35 – 100.36 Mb	Chr 19: 44.39 – 44.41 Mb
PubMed search	[1]	[2]

Stearoyl-CoA desaturase (delta-9-desaturase) is a protein that in humans is encoded by the SCD gene.

Stearoyl-CoA desaturase-1 is a key enzyme in fatty acid metabolism. It is responsible for forming a double bond in Stearoyl-CoA. This is how the monounsaturated fatty acid oleic acid is produced from the saturated fatty acid stearic acid.

Function

Stearoyl-CoA desaturase (SCD; EC 1.14.19.1) is an iron-containing enzyme that catalyzes a rate-limiting step in the synthesis of unsaturated fatty acids. The principal product of SCD is oleic acid, which is formed by desaturation of stearic acid. The ratio of stearic acid to oleic acid has been implicated in the regulation of cell growth and differentiation through effects on cell membrane fluidity and signal transduction. Four SCD isoforms, Scd1 through Scd4, have been identified in mouse. In contrast, only 2 SCD isoforms, SCD1 and SCD5 (MIM 608370), have been identified in human. SCD1 shares about 85% amino acid identity with all 4 mouse SCD isoforms, as well as with rat Scd1 and Scd2. In contrast, SCD5 shares limited homology with the rodent SCDs and appears to be unique to primates.

Role in human disease

Elevated expression levels of SCD1 is found to be correlated with obesity and tumor malignancy. It is believed that tumor cells obtain most part of their requirement for fatty acids by de novo synthesis. This phenomenon depends on increased expression of fatty acid biosynthetic enzymes that produce required fatty acids in large quantities.

SCD1 function has also been shown to be involved in germ cell determination, adipose tissue specification, liver cell differentiation and cardiac development.

External links

• Stearoyl-CoA Desaturase at the US National Library of Medicine Medical Subject Headings (MeSH)