Indole-3-acetic acid

Indole-3-acetic acid

Names
IUPAC name 2-(1H-indol-3-yl)acetic acid
Systematic IUPAC name 2-(1H-indol-3-yl)ethanoic acid
Other names Indole-3-acetic acid, indolylacetic acid, 1H-Indole-3-acetic acid, indoleacetic acid, heteroauxin, IAA
Identifiers
CAS Number	87-51-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16411 Y
ChemSpider	780 Y
DrugBank	DB07950 Y
ECHA InfoCard	100.001.590
KEGG	C00954 Y
PubChem CID	802
InChI InChI=1S/C10H9NO2/c12-10(13)5-7-6-11-9-4-2-1-3-8(7)9/h1-4,6,11H,5H2,(H,12,13) Y Key: SEOVTRFCIGRIMH-UHFFFAOYSA-N Y InChI=1/C10H9NO2/c12-10(13)5-7-6-11-9-4-2-1-3-8(7)9/h1-4,6,11H,5H2,(H,12,13) Key: SEOVTRFCIGRIMH-UHFFFAOYAT
SMILES O=C(O)Cc2c1ccccc1nc2
Properties
Chemical formula	C10H9NO2
Molar mass	175.19 g·mol−1
Appearance	White solid
Melting point	168 to 170 °C (334 to 338 °F; 441 to 443 K)
Solubility in water	Moderate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Indole-3-acetic acid (IAA, 3-IAA) is the most common, naturally occurring, plant hormone of the auxin class. It is the best known of the auxins, and has been the subject of extensive studies by plant physiologists. IAA is a derivative of indole, containing a carboxymethyl substituent. It is a colorless solid that is soluble in polar organic solvents.

IAA is predominantly produced in cells of the apex (bud) and very young leaves of a plant. Plants can synthesize IAA by several independent biosynthetic pathways. Four of them start from tryptophan, but there is also a biosynthetic pathway independent of tryptophan. Plants mainly produce IAA from tryptophan through indole-3-pyruvic acid. IAA is also produced from tryptophan through indole-3-acetaldoxime in Arabidopsis thaliana.

In rats, IAA is a product of both endogenous and colonic microbial metabolism from dietary tryptophan along with tryptophol. This was first observed in rats infected by Trypanosoma brucei gambiense. and correlation with protein intake has been confirmed in 2015. Humans did not excrete IAA.

As all auxins, IAA has many different effects, such as inducing cell elongation and cell division with all subsequent results for plant growth and development. On a larger scale, IAA serves as signaling molecule necessary for development of plant organs and coordination of growth.

IAA enters the plant cell nucleus and binds to a protein complex composed of a ubiquitin-activating enzyme (E1), a ubiquitin-conjugating enzyme (E2), and a ubiquitin ligase (E3), resulting in ubiquitination of Aux/IAA proteins with increased speed. Aux/IAA proteins bind to auxin response factor (ARF) proteins, forming a heterodimer, suppressing ARF activity. In 1997 it was described how ARF's bind to auxin-response gene elements in promoters of auxin regulated genes, generally activating transcription of that gene when an Aux/IAA protein is not bound.