trans-urocanic acid (trans-UCA) is a natural epidermal component that can inhibit human natural killer cell activity in vitro. trans-urocanic acid effectively modulates immune function.

Physicochemical Properties

Molecular Formula	C6H6N2O2
Molecular Weight	138.12
Exact Mass	138.042
CAS #	3465-72-3
Related CAS #	Urocanic acid;104-98-3;cis-Urocanic acid;7699-35-6
PubChem CID	736715
Appearance	Off-white to light yellow solid powder
Density	1.4±0.1 g/cm3
Boiling Point	456.9±20.0 °C at 760 mmHg
Flash Point	230.1±21.8 °C
Vapour Pressure	0.0±1.2 mmHg at 25°C
Index of Refraction	1.674
LogP	0.01
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	2
Heavy Atom Count	10
Complexity	156
Defined Atom Stereocenter Count	0
SMILES	C1=C(NC=N1)/C=C/C(=O)O
InChi Key	LOIYMIARKYCTBW-OWOJBTEDSA-N
InChi Code	InChI=1S/C6H6N2O2/c9-6(10)2-1-5-3-7-4-8-5/h1-4H,(H,7,8)(H,9,10)/b2-1+
Chemical Name	(E)-3-(1H-imidazol-5-yl)prop-2-enoic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Human Endogenous Metabolite
ln Vitro	Trans-urocanic acid (trans-UCA) diminishes NK cell activation mediated by IL-2 and partially inhibits the cytotoxic action of NK cells that have been activated by IL-2[1]. Trans-urocanic acid (trans-UCA; 100 μg/mL) marginally reduces primary human keratinocyte viability and cell proliferation[2].
Cell Assay	Cell Proliferation Assay[2] Cell Types: Primary human keratinocytes Tested Concentrations: 100 μg/mL Incubation Duration: 24 hrs (hours) Experimental Results: diminished cell proliferation and viability.
References	[1]. Trans-urocanic acid, a natural epidermal constituent, inhibits human natural killer cell activity in vitro. Exp Dermatol. 1994 Apr;3(2):61-5. [2]. cis-Urocanic acid enhances prostaglandin E2 release and apoptotic cell death via reactive oxygen species in human keratinocytes. J Invest Dermatol. 2011 Jun;131(6):1262-71.
Additional Infomation	Urocanic acid is an alpha,beta-unsaturated monocarboxylic acid that is prop-2-enoic acid substituted by a 1H-imidazol-4-yl group at position 3. It is a metabolite of hidtidine. It has a role as a chromophore and a human metabolite. It is an alpha,beta-unsaturated monocarboxylic acid and a member of imidazoles. It is a conjugate acid of a urocanate. Urocanic acid is a metabolite found in or produced by Escherichia coli (strain K12, MG1655). Urocanic acid has been reported in Homo sapiens, Hippospongia communis, and other organisms with data available. 4-Imidazoleacrylic acid.

Solubility Data

Solubility (In Vitro)

DMSO: 100 mg/mL (724.01 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (18.10 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (18.10 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.5 mg/mL (18.10 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	7.2401 mL	36.2004 mL	72.4008 mL
	5 mM	1.4480 mL	7.2401 mL	14.4802 mL
	10 mM	0.7240 mL	3.6200 mL	7.2401 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.