46065

Ethidium bromide

for fluorescence, ≥95.0% (HPLC)

• Synonym(s): 3,8-Diamino-5-ethyl-6-phenylphenanthridinium bromide, EtBr, Homidium bromide
• Empirical Formula (Hill Notation): C₂₁H₂₀BrN₃
• CAS Number: 1239-45-8
• Molecular Weight: 394.31
• Beilstein: 3642536
• EC Number: 214-984-6
• MDL number: MFCD00011724
• UNSPSC Code: 12352200
• PubChem Substance ID: 57650683

Properties

• grade: for fluorescence
• Assay: ≥95.0% (HPLC)
• mp: 260-262 °C (dec.) (lit.)
• solubility: H₂O: 10 mg/mL, opaque, very dark red
• fluorescence: λ_ex 480 nm; λ_em 620 nm in H₂O; λ_ex 530 nm; λ_em 600 nm in 50 mM phosphate buffer pH 7.0 (upon binding to DNA)
• SMILES string: [Br-].CC[n+]1c(-c2ccccc2)c3cc(N)ccc3c4ccc(N)cc14
• InChI: 1S/C21H19N3.BrH/c1-2-24-20-13-16(23)9-11-18(20)17-10-8-15(22)12-19(17)21(24)14-6-4-3-5-7-14;/h3-13,23H,2,22H2,1H3;1H
• InChI key: ZMMJGEGLRURXTF-UHFFFAOYSA-N

Description

General description

Ethidium bromide (EtBr) undergoes complexation with nucleic acids (DNA and RNA) specifically to the saturated sites. These complexes decomposes by employing a cation-exchange resin. It has been reported to inhibit the production of mitochondrial RNA in HeLa cells. On interaction with helical polynucleotides under high salt medium, it forms fluorescent complex (having high fluorescence quantum yield).

Application

Ethidium bromide (EtBr) is the most commonly used nucleic acid stain for PAGE or agarose gel electrophoresis. The fluorescence of EtBr increases 21-fold upon binding to double-stranded RNA and 25-fold on binding double-stranded DNA so that destaining the background is not necessary with a low stain concentration (10 μg/ml). Ethidium bromide has been used in a number of fluorimetric assays for nucleic acids. It has been shown to bind to single-stranded DNA (although not as strongly) and triple-stranded DNA. Because of its ability to bind to DNA, EtBr is an inhibitor of DNA polymerase.

Frameshift mutagen which intercalates double-stranded DNA and RNA.

Ethidium bromide has been used to prepare fluorescent stock solution for the evaluation of cell viability during the live/dead assay of adipose-derived stem cells (ADSCs) seeded on irradiated hydrogels.

Biochem/physiol Actions

Ethidium bromide intercalates double-stranded DNA and RNA and acts as a frameshift mutagen. It can also be used in conjunction with acridine orange to differentiate between viable, apoptotic and necrotic cells.

Reconstitution

For staining a gel after electrophoresis, dilute a sample of the stock solution to 0.5 μg/ml with water and incubate the gel for 15-30 min. Destaining is usually not needed but can be carried out in water for 15 min if decreased background is necessary. The DNA bands can then be detected on a UV light box (254 nm wavelength). Ethidium bromide can also be incorporated into the gel and running buffer at 0.5 μg/ml and visualized immediately after electrophoresis.

Other Notes

Intercalating agent and fluorescent label for DNA. Review; Destruction and decontamination of solutions

Safety Information

• Pictograms: GHS06,GHS08
• Signal Word: Danger
• Hazard Statements: H302,H330,H341
• Precautionary Statements: P202 - P260 - P264 - P270 - P301 + P312 - P304 + P340 + P310
• Hazard Classifications: Acute Tox. 1 Inhalation - Acute Tox. 4 Oral - Muta. 2
• Storage Class Code: 6.1A - Combustible acute toxic Cat. 1 and 2 / very toxic hazardous materials
• WGK: WGK 1
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves