DRB

Synonym(s):5,6-Dichloro-1-β-D-ribofuranosylbenzimidazole;5,6-Dichloro-1-β-D-ribofuranosylbenzimidazole - CAS 53-85-0 - Calbiochem;5,6-Dichlorobenzimidazole riboside;5,6-Dichlorobenzimidazole Riboside, DRB, Casein Kinase II Inhibitor VII;DRB

CAS NO.：53-85-0
Empirical Formula: C12H12Cl2N2O4
Molecular Weight: 319.14
MDL number: MFCD00036785
SAFETY DATA SHEET (SDS)
Update Date: 2024-11-07 13:31:19

What is DRB?

Description

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

Chemical properties

White Solid

The Uses of DRB

DRB is an inhibitor of RNA synthesis (causes premature termination of transcription).

The Uses of DRB

Inhibits casein kinase II and blocks RNA synthesis. An adenosine analog.5,6-Dichlorobenzimidazole riboside is used as an inhibitor of RNA Polymerase II. It is nucleoside analogue and used in research to study the mechanisms of cellular regulation. Further, it inhibits some protein kinases.

The Uses of DRB

5,6-Dichlorobenzimidazole 1-β-D-ribofuranoside has been used:

as an inhibitor of RNA polymerase II in mouse melanoma cells
for the inhibition of cyclin D1 mRNA synthesis in human prostate epithelial cell lines
in the inhibition of interleukin-2 gene transcription in Jurkat cells

What are the applications of Application

DRB is an adenosine analogue which interrupts DNA transcription

Biochem/physiol Actions

5,6-Dichlorobenzimidazole 1-β-D-ribofuranoside (DRB), a nucleoside analog that halts mRNA synthesis by phosphorylation of the C-terminal domain of RNA polymerase II, making it inactive. It also interferes with the DNA topoisomerase II, may modulate response to cytokines and blocks the human immunodeficiency virus (HIV) via RNA modification. It also inhibits cyclin-dependent kinases (CDKs) 7 and 9 and favors apoptosis in leukemic cells. It may serve as a therapeutic agent in treating cancer.

References

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

Properties of DRB

Melting point:	222-224°C
Boiling point:	606.2±65.0 °C(Predicted)
Density	1.5917 (rough estimate)
refractive index	1.6200 (estimate)
storage temp.	-20°C
solubility	Soluble in DMSO (up to 20 mg/ml)
form	White solid
pka	13.23±0.70(Predicted)
color	White
Water Solubility	Soluble in DMSO to 75mMSoluble in dimethyl sulfoxide, hot ethanol, dimethyl formamide, (1:2) dimethyl formamide:Phosphate buffer saline, water, methanol and pyridine. Slightly soluble in aqueous buffers.
λmax	296nm(lit.)
BRN	39123
Stability:	Stable for 1 year from date of purchase as supplied. Solutions in DMSO may be stored at -20°C for up to 3 months.
CAS DataBase Reference	53-85-0

Safety information for DRB

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H315:Skin corrosion/irritation H319:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.