U-0126, 10 mg

This small molecule from STEMCELL Technologies is a selective, non-ATP competitive inhibitor of mitogen-activated protein kinase kinase (MEK), targeting MEK1 and MEK2. The active component is 2,3-bis[amino[(2-aminophenyl)thio]methylene]-butanedinitrile (CAS 109511-58-2), with the molecular formula C18H16N6S2 and a molecular weight of 380.5 g/mol. It is supplied as a crystalline solid at a stated purity of ≥ 98%.

In published characterization, the compound inhibits MEK1 and MEK2 with IC50 values of 72 nM and 58 nM, respectively, while showing little or no inhibition at micromolar concentrations of ERK, protein kinase C, c-Jun N-terminal kinases, MKK3, MKK4, MKK6, CDK2, CDK4, ABL, and RAF. It additionally antagonizes AP-1 transcription and selectively inhibits promoters containing AP-1 response elements.

Reported solubility values include ~0.3 mg/mL in a 1:2 solution of DMF:PBS (pH 7.2), ~0.5 mg/mL in EtOH, ~25 mg/mL in DMSO, and ~30 mg/mL in DMF. The product is documented as stable at -20°C as supplied and should be protected from prolonged exposure to light. Reported maximum stock concentrations are ≤ 65 mM in DMSO and ≤ 1 mM in absolute ethanol. The compound has low solubility in aqueous media, and a final DMSO concentration above 0.1% should be avoided due to potential cell toxicity. The safety data sheet classifies the substance as not hazardous under the 2012 OSHA Hazard Communication Standard or the GHS, and reports it as chemically stable under normal conditions. Incompatible materials include strong oxidizing agents, and hazardous decomposition products include carbon dioxide, carbon monoxide, hydrogen sulfide gas, and nitrogen oxides.