Urocanic acid

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Urocanic acid
Names
Preferred IUPAC name
(2E)-3-(1H-imidazol-4-yl)prop-2-enoic acid
Other names
(E)-3-(1H-imidazol-4-yl)acrylic acid
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
 100.002.963 Edit this at Wikidata
MeSH Urocanic+acid
UNII
  • InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1+ ☒N
    Key: LOIYMIARKYCTBW-OWOJBTEDSA-N ☒N
  • InChI=1/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1+
    Key: LOIYMIARKYCTBW-OWOJBTEDBA
  • c1c(nc[nH]1)/C=C/C(=O)O
Properties
C6H6N2O2
Molar mass 138.124 g/mol
Melting point 225 °C (437 °F; 498 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Urocanic acid (formally trans-Urocanic acid) is an intermediate in the

cis-urocanic acid
isomer is rare.

Metabolism

It is formed from L-histidine through the action of

histidine ammonialyase
(also known as histidase or histidinase) by elimination of ammonium.

In the liver, urocanic acid is transformed by

4-imidazolone-5-propionic acid and subsequently to glutamic acid
.

Clinical significance

Inherited deficiency of urocanase leads to elevated levels of urocanic acid in the urine, a condition known as urocanic aciduria.

An important role for the onset of atopic dermatitis and asthma has been attributed to filaggrin, a skin precursor of urocanic acid.[1][2]

Urocanic acid is thought to be a significant attractant of the nematode parasite Strongyloides stercoralis,[3] in part because of relatively high levels in the plantar surfaces of the feet, the site through which this parasite often enters the body.

Function

Urocanic acid was detected in animal sweat and skin where, among other possible functions, it acts as an endogenous sunscreen or photoprotectant against

regulatory T cells.[5]

Some studies attribute filaggrin an important role in keeping the skin surface slightly acidic, through a breaking down mechanism to form histidine and subsequently trans-urocanic acid,[6] however others have shown that the filaggrin–histidine–urocanic acid cascade is not essential for skin acidification.[7]

History

Urocanic acid was first isolated in 1874 by the chemist

Latin
: urina = urine, and canis = dog).

See also

References

  1. PMID 28025545
    .
  2. PMID 21991953
    .
  3. PMID 17234810
    .
  4. PMID 20442934
    .
  5. PMID 16452825
    .
  6. S2CID 24679127
    .
  7. PMID 20376063
    .
  8. doi:10.1002/cber.187500801267
    .
  9. doi:10.1002/cber.187400702225
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Urocanic_acid&oldid=1215439625"