tartronic acid semialdehyde
{{Chembox
| ImageFile = Tartronic acid hemialdehyde.svg
| ImageSize =
| ImageAlt =
| IUPACName =
| OtherNames = Tartronaldehydic acid
2-hydroxy-3-oxopropanoic acid
formyl(hydroxy)acetic acid
Hydroxymalonaldehydic acid
|Section1={{Chembox Identifiers
| CASNo = 2480-77-5
| CASNo_Ref = {{Cascite|correct|CAS}}
| ChEBI = 16992
| ChemSpiderID = 1090
| KEGG = C01146
| PubChem = 1122
| StdInChI=1S/C3H4O4/c4-1-2(5)3(6)7/h1-2,5H,(H,6,7)
| StdInChIKey = QWBAFPFNGRFSFB-UHFFFAOYSA-N
| SMILES = C(=O)C(C(=O)O)O
}}
|Section2={{Chembox Properties
| C = 3|H=4|O=4
| MolarMass =
| Appearance = white solid
| Density =
| MeltingPt =
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
Tartronic acid semialdehyde is the organic compound with the formula OCHCH(OH)CO2H. The molecule has three functional groups, aldehyde, alcohol, and carboxylic acid. A white solid, it occurs naturally. At near neutral pH, it exists as the hydrated carboxylate (HO)2CHCH(OH)CO2−, which is referred to as tartronate semialdehyde. Tartronate semialdehyde is produced and consumed on a prodigious scale as an intermediate in photorespiration, an undesirable side reaction that competes with photosynthesis. It is produced biologically by the condensation of two equivalents of glyoxalate:{{cite journal | vauthors = Leegood RC | title = A Welcome Diversion from Photorespiration | journal = Nature Biotechnology | volume = 25 | issue = 5 | pages = 539–40 | date = May 2007 | pmid = 17483837 | doi = 10.1038/nbt0507-539 | s2cid = 5015366 }}
:2{{nbsp}}OC(H)CO2H → OC(H)CH(OH)CO2H + CO2
This condensation is catalyzed by tartronate-semialdehyde synthase.