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Details

Stereochemistry ACHIRAL
Molecular Formula C6H6N2O2
Molecular Weight 138.124
Optical Activity NONE
Defined Stereocenters 0 / 0
E/Z Centers 1
Charge 0

SHOW SMILES / InChI
Structure of UROCANIC ACID

SMILES

OC(=O)\C=C\C1=CNC=N1

InChI

InChIKey=LOIYMIARKYCTBW-OWOJBTEDSA-N
InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1+

HIDE SMILES / InChI

Molecular Formula C6H6N2O2
Molecular Weight 138.124
Charge 0
Count
MOL RATIO 1 MOL RATIO (average)
Stereochemistry ACHIRAL
Additional Stereochemistry No
Defined Stereocenters 0 / 0
E/Z Centers 1
Optical Activity NONE

Description

Urocanic acid is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e. g. , pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. It has also been proposed that c-UA may mediate the transient alteration in immune surveillance resulting in immunosuppression induced after UV-irradiation, by interacting with immune cells locally and/or systemically to generate T cells with suppressor function.

Approval Year

Targets

Primary TargetPharmacologyConditionPotency
354.0 µM [IC50]
4.6 nM [Kd]

PubMed

Sample Use Guides

In Vitro Use Guide
A combination of the trans- and cis-isomers of urocanic acid (200 ug/ml) induced cAMP in both CD16+ and CD16- cells, but individual, stereospecific effects were not demonstrable.
Substance Class Chemical
Record UNII
G8D26XJJ3B
Record Status Validated (UNII)
Record Version