U120 Sigma

U0126 monoethanolate

≥98% (HPLC), powder

Synonym: 1,4-Diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene monoethanolate

  • Empirical Formula (Hill Notation) C18H16N6S2 · C2H5OH

  • Molecular Weight 426.56

  •  MDL number MFCD25977152

  •  PubChem Substance ID 24278770



Related Categories Bioactive Small Molecule Alphabetical Index, Bioactive Small Molecules, Cell Biology, Cell Signaling and Neuroscience, Kinase/Phosphatase Biology,
assay   ≥98% (HPLC)
form   powder
storage condition   protect from light
color   white to off-white
solubility   DMSO: >10 mg/mL (Stock solutions in DMSO should be used within a month. Acidic solutions exhibit weaker inhibition)
storage temp.   2-8°C
Gene Information   human ... MAP2K1(5604), MAP2K2(5605)





1, 5 mg in glass bottle

Preparation Note

U0126 monoethanolate is soluble in DMSO at a concentration >10 mg/ml. Stock solutions of the product in DMSO should be used within a month. Acidic solutions of the product exhibit weaker MEK inhibitory functions.


U0126 monoethanolate has been used as an MEK inhibitor in mononucleated myogenic cells derived from breast muscles of chicken embryos. U0126 has also been used to study ERK2 function in amyloid precursor protein (APP) knockout (KO) mice neurons.

Biochem/physiol Actions

U0126, 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene, is a highly selective inhibitor of both MEK1 and MEK2. U0126 was found to functionally antagonize AP-1 transcriptional activity via noncompetitive inhibition of the dual specificity kinase MEK with IC50 of 72 nM for MEK1 and 58 nM for MEK2. U0126 inhibited anchorage-independent growth of Ki-ras-transformed rat fibroblasts by simultaneously blocking both extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR)-p70(S6K) pathways. The effects of U0126 on the growth of eight human breast cancer cell lines shown that U0126 selectively repressed anchorage-independent growth of MDA-MB231 and HBC4 cells, two lines with constitutively activated ERK. Loss of contact with substratum triggers apoptosis in many normal cell types, a phenomenon termed anoikis. U0126 sensitized MDA-MB231 and HBC4 to anoikis, i.e., upon treatment with U0126, cells deprived of anchorage entered apoptosis.

Features and Benefits

This compound is a featured product for Kinase Phosphatase Biology research. Click here to discover more featured Kinase Phosphatase Biology products. Learn more about bioactive small molecules for other areas of research at

This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more.

This compound is featured on the MAPKs page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.

Legal Information

LOPAC is a registered trademark of Sigma-Aldrich Co. LLC

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 

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