U0126 monoethanolate

≥98% (HPLC), powder

1,4-Diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene monoethanolate
Empirical Formula (Hill Notation):
C18H16N6S2 · C2H5OH
Molecular Weight:
MDL number:
PubChem Substance ID:
Pricing and availability is not currently available.

Quality Level


≥98% (HPLC)



storage condition

protect from light


white to off-white


DMSO: >10 mg/mL (Stock solutions in DMSO should be used within a month. Acidic solutions exhibit weaker inhibition)

storage temp.


SMILES string




InChI key


Gene Information

human ... MAP2K1(5604), MAP2K2(5605)


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.


1, 5 mg in glass bottle

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 sigma.com/discover-bsm.
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.



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.

Legal Information

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

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Andrew J Billnitzer et al.
Journal of neurochemistry, 124(1), 123-132 (2012-10-16)
Amyloid precursor protein (APP) and its secreted form, sAPP, contribute to the development of neurons in hippocampus, a brain region critical for learning and memory. Full-length APP binds the low-density lipoprotein receptor-related protein (LRP), which stimulates APP endocytosis. LRP also...
Xiao-Yang Wang et al.
Molecular and cellular biology, 28(11), 3589-3599 (2008-03-26)
The RNA-binding protein Musashi1 (Msi1) is a positive regulator of Notch-mediated transcription in Drosophila melanogaster and neural progenitor cells and has been identified as a putative human breast stem cell marker. Here we describe a novel functional role for Msi1:...
Yi Xiao et al.
Cellular and molecular gastroenterology and hepatology, 8(1), 21-36 (2019-03-05)
Regenerating islet-derived protein (REG3γ), an antimicrobial peptide, typically expressed by intestinal epithelial cells (IEC), plays crucial roles in intestinal homeostasis and controlling gut microbiota. However, the mechanisms that regulate IEC expression of REG3γ are still largely unclear. In this study...
D R DeSilva et al.
Journal of immunology (Baltimore, Md. : 1950), 160(9), 4175-4181 (1998-05-09)
Three mitogen-activated protein kinase pathways are up-regulated during the activation of T lymphocytes, the extracellular signal-regulated kinase (ERK), Jun NH2-terminal kinase, and p38 mitogen-activated protein kinase pathways. To examine the effects of blocking the ERK pathway on T cell activation...
Alessandra Ciullo et al.
International journal of molecular sciences, 20(3) (2019-01-27)
Cell therapy has been evaluated to enhance heart function after injury. Delivered cells mostly act via paracrine mechanisms, including secreted growth factors, cytokines, and vesicles, such as exosomes (Exo). Intramyocardial injection of cardiac-resident progenitor cells (CPC)-derived Exo reduced scarring and...
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