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.[1] IAA is a derivative of indole, containing a carboxymethyl substituent. It is a colorless solid that is soluble in polar organic solvents.
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.[8] Aux/IAA proteins bind to auxin response factor (ARF) proteins, forming a heterodimer, suppressing ARF activity.[9] 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.
IAA inhibits the photorespiratory-dependent cell death in photorespiratory catalase mutants. This suggests a role for auxin signalling in stress tolerance.
- Cas no: 87-51-4
- Formula: C10H9NO2
- Molar mass: 175.184 g/mol
- Solubility in water: insoluble in water. Soluble in ethanol to 50mg/ml
- Melting point: 168 to 170 °C (334 to 338 °F; 441 to 443 K)
- Appearance: White solid
- PubChem CID: 802