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Product Details

DRB | Transcription inhibitor, CK2 inhibitor

DRB (53-85-0) is a classic inhibitor of transcription by RNA polymerase II. A relatively selective inhibitor of Cdk9 (IC50=3 μM), the kinase of the positive transcription elongation factor b (P-TEF-b) required for processive transcription elongation by RNA polymerase II.1,2 Also inhibits casein kinase II, IC50=4-10 μM. 3 Suppresses the SIRT1/CK2α pathway and enhances the radiosensitivity of human cancer cells.4 Kinase-independent activities of Cdk9 such as glucocorticoid receptor modulation are not inhibited by DRB.5


1) Baumli et al. (2010), Halogen bonds form the basis for selective P-TEFb inhibition by DRB; Chem. Biol., 17 931
2) Yamaguchi et al. (1998), Interplay between positive and negative elongation factors: drawing a new view of DRB; Genes Cells, 3 9
3) Zandomeni (1989), Kinetics of inhibition by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole; Biochem.J., 262 469
4) Wang et al. (2014), Inhibition of P-TEFb by DRB suppresses SIRT1/CK2α pathway and enhances radiosensitivity of human cancer cells; Anticancer Res., 34 6981
5) Zhu et al. (2014), A kinase-independent activity of Cdk9 modulates glucocorticoid receptor-mediated gene induction; Biochemistry, 53 1753

Focus Biomolecules cell signaling supplier, chemical structure of DRB | Transcription inhibitor, CK2 inhibitor | CAS 53-85-0

Catalog#  10-2047-0010

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Catalog Number:
Transcription inhibitor, CK2 inhibitor
Chemical Name:
Alternate Names:
5,6-Dichlorobenzimidazole riboside; NSC 401575
Molecular Weight:
Molecular Formula:
Soluble in DMSO (up to 20 mg/ml)
Physical Properties:
White solid
98% by HPLC
NMR (Conforms)
Storage Temperature:
-20°C (des.)
Stable for 1 year as supplied. Solutions in DMSO may be stored at -20°C for up to 3 months.
Shipping Code:
Materials provided by Focus Biomolecules are for laboratory research use only and are not intended for human or veterinary applications.

Focus BiomoleculesPlymouth Meeting, PA USA1-855-FOCUS21

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