Retinoic acid

All-*trans*-retinoic acid
Names
	IUPAC name Retinoic acid
	Systematic IUPAC name (2E,4E,6E,8E)-3,7-Dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenoic acid
	Other names vitamin A acid; RA
Identifiers
CAS Number	302-79-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:15367;
ChEMBL	ChEMBL38 ;
ChemSpider	392618;
IUPHAR/BPS	2644;
PubChem CID	444795;
UNII	5688UTC01R ;
	InChI InChI=1S/C20H28O2/c1-15(8-6-9-16(2)14-19(21)22)11-12-18-17(3)10-7-13-20(18,4)5/h6,8-9,11-12,14H,7,10,13H2,1-5H3,(H,21,22)/b9-6+,12-11+,15-8+,16-14+ Key: SHGAZHPCJJPHSC-YCNIQYBTSA-N;
	SMILES CC1=C(C(CCC1)(C)C)/C=C/C(=C/C=C/C(=C/C(=O)O)/C)/C;
Properties
Chemical formula	C20H28O2
Molar mass	300.43512 g/mol
Appearance	yellow to light orange crystalline powder with a characteristic of a floral scent
Melting point	180 to 182 °C (356 to 360 °F; 453 to 455 K) crystals from ethanol
Solubility in water	nearly insoluble
Solubility in fat	soluble
Related compounds
Related compounds	retinol; retinal; beta-carotene
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Retinoic acid (used simplified here for all-trans-retinoic acid) is a metabolite of vitamin A₁ (all-trans-retinol) that mediates the functions of vitamin A₁ required for growth and development. All-trans-retinoic acid is required in chordate animals, which includes all higher animals from fish to humans. During early embryonic development, all-trans-retinoic acid generated in a specific region of the embryo helps determine position along the embryonic anterior/posterior axis by serving as an intercellular signaling molecule that guides development of the posterior portion of the embryo.^[2] It acts through Hox genes, which ultimately control anterior/posterior patterning in early developmental stages.^[3]

All-trans-retinoic acid (ATRA) is the major occurring retinoic acid, while isomers like 13-cis- and 9-cis-retinoic acid are also present in much lower levels.^[4]

The key role of all-trans-retinoic acid in embryonic development mediates the high teratogenicity of retinoid pharmaceuticals, such as isotretinoin (13-cis-retinoic acid) used for treatment of cancer and acne. Oral megadoses of preformed vitamin A (retinyl palmitate), and all-trans-retinoic acid itself, also have teratogenic potential by this same mechanism.

^ ^a ^b Merck Index, 13th Edition, 8251.
^ Duester G (September 2008). "Retinoic acid synthesis and signaling during early organogenesis". Cell. 134 (6): 921–31. doi:10.1016/j.cell.2008.09.002. PMC 2632951. PMID 18805086.
^ Holland LZ (May 2007). "Developmental biology: a chordate with a difference". Nature. 447 (7141): 153–5. Bibcode:2007Natur.447..153H. doi:10.1038/447153a. PMID 17495912. S2CID 5549210.
^ Rühl R, Krezel W, de Lera AR (December 2018). "9-Cis-13,14-dihydroretinoic acid, a new endogenous mammalian ligand of retinoid X receptor and the active ligand of a potential new vitamin A category: vitamin A5". Nutrition Reviews. 76 (12): 929–941. doi:10.1093/nutrit/nuy057. PMID 30358857.

[Merck-1] Merck Index, 13th Edition, 8251.

[Duester-2] Duester G (September 2008). "Retinoic acid synthesis and signaling during early organogenesis". Cell. 134 (6): 921–31. doi:10.1016/j.cell.2008.09.002. PMC 2632951. PMID 18805086.

[Holland-3] Holland LZ (May 2007). "Developmental biology: a chordate with a difference". Nature. 447 (7141): 153–5. Bibcode:2007Natur.447..153H. doi:10.1038/447153a. PMID 17495912. S2CID 5549210.

[Rühl_2018-4] Rühl R, Krezel W, de Lera AR (December 2018). "9-Cis-13,14-dihydroretinoic acid, a new endogenous mammalian ligand of retinoid X receptor and the active ligand of a potential new vitamin A category: vitamin A5". Nutrition Reviews. 76 (12): 929–941. doi:10.1093/nutrit/nuy057. PMID 30358857.

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