Catalog No. size PriceQuantity
M6484-2 2mg solid $134
M6484-10 10mg solid $522



Product Information:

STO-609 is a specific inhibitor of the Ca(2+)/calmodulin-dependent protein kinase kinase. STO-609 inhibits the activities of recombinant CaM-KK alpha and CaM-KK beta isoforms, with K(i) values of 80 and 15 ng/ml, respectively, and also inhibits their autophosphorylation activities. STO-609 is highly selective for CaM-KK without any significant effect on the downstream CaM kinases (CaM-KI and -IV), and the IC(50) value of the compound against CaM-KII is approximately 10 microg/ml. STO-609 is a selective and cell-permeable inhibitor of CaM-KK and that it may be a useful tool for evaluating the physiological significance of the CaM-KK-mediated pathway in vivo as well as in vitro.


Chemical Formula: C19H10N2O3


Exact Mass: 314.0691


Molecular Weight: 314.3


Elemental Analysis: C, 72.61; H, 3.21; N, 8.91; O, 15.27





STO 609



Chemical Name:

7-oxo-7H-benzo[de]benzo[4,5]imidazo[2,1-a]isoquinoline-3-carboxylic acid


InChi Key:



InChi Code: 



Smiles Code:




Technical Data:


Appearance: Yellow solid powder

Purity: >98% (or refer to the Certificate of Analysis)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition: Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Solubility: Soluble in DMSO

Shelf Life: >2 years if stored properly

Drug Formulation: This drug may be formulated in DMSO

Stock Solution Storage: 0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code: 2934.99.9001


In Vitro:

STO-609 inhibits the activities of recombinant CaM-KKα and CaM-KKβ isoforms, with Ki values of 80 and 15 ng/mL, respectively, and also inhibits their autophosphorylation activities. STO-609 is highly selective for CaM-KK without any significant effect on the downstream CaM kinases (CaM-KI and -IV), and the IC50 value of the compound against CaM-KII is 10 μg/mL. STO-609 inhibits constitutively active CaM-KKα as well as the wild-type enzyme. In transfected HeLa cells, STO-609 suppresses the Ca2+-induced activation of CaM-KIV in a dose-dependent manner. STO-609 significantly reduces the endogenous activity of CaM-KK in SH-SY5Y neuroblastoma cells at a concentration of 1μg/mL (80% inhibitory rate).





  1. Gerner L, Munack S, Temmerman K, Lawrence-Dörner AM, Besir H, Wilmanns M, Jensen JK, Thiede B, Mills IG, Morth JP. Using the fluorescent properties of STO-609 as a tool to assist structure-function analyses of recombinant CaMKK2. Biochem Biophys Res Commun. 2016 Jul 22;476(2):102-7. doi: 10.1016/j.bbrc.2016.05.045. PubMed PMID: 27178209.


  1. Fujiwara Y, Hiraoka Y, Fujimoto T, Kanayama N, Magari M, Tokumitsu H. Analysis of Distinct Roles of CaMKK Isoforms Using STO-609-Resistant Mutants in Living Cells. Biochemistry. 2015 Jun 30;54(25):3969-77. doi: 10.1021/acs.biochem.5b00149. PubMed PMID: 26050738.


  1. Ma Z, Wen D, Wang X, Yang L, Liu T, Liu J, Zhu J, Fang X. Growth inhibition of human gastric adenocarcinoma cells in vitro by STO-609 is independent of calcium/calmodulin-dependent protein kinase kinase-beta and adenosine monophosphate-activated protein kinase. Am J Transl Res. 2016 Feb 15;8(2):1164-71. PubMed PMID: 27158402; PubMed Central PMCID: PMC4846959.


  1. Kukimoto-Niino M, Yoshikawa S, Takagi T, Ohsawa N, Tomabechi Y, Terada T, Shirouzu M, Suzuki A, Lee S, Yamauchi T, Okada-Iwabu M, Iwabu M, Kadowaki T, Minokoshi Y, Yokoyama S. Crystal structure of the Ca²⁺/calmodulin-dependent protein kinase kinase in complex with the inhibitor STO-609. J Biol Chem. 2011 Jun 24;286(25):22570-9. doi: 10.1074/jbc.M111.251710. PubMed PMID: 21504895; PubMed Central PMCID: PMC3121401.


  1. Monteiro P, Gilot D, Langouet S, Fardel O. Activation of the aryl hydrocarbon receptor by the calcium/calmodulin-dependent protein kinase kinase inhibitor 7-oxo-7H-benzimidazo[2,1-a]benz[de]isoquinoline-3-carboxylic acid (STO-609). Drug Metab Dispos. 2008 Dec;36(12):2556-63. doi: 10.1124/dmd.108.023333. PubMed PMID: 18755850.


Products are for research use only. Not for human use.


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