46067

Ethidium bromide solution

for fluorescence, ~1% in H₂O

• 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
• MDL number: MFCD00011724
• UNSPSC Code: 12161505
• PubChem Substance ID: 57650684
• NACRES: NA.32

Properties

• grade: for fluorescence
• concentration: ~1% in H₂O
• fluorescence: λ_ex 480 nm; λ_em 620 nm in H₂O; λ_ex 518 nm; λ_em 605 nm (bound to DNA); λ_ex 530 nm; λ_em 600 nm in 50 mM phosphate buffer pH 7.0 (upon binding to DNA)
• storage temp.: 2-8°C
• 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

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.

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.

Safety Information

• Pictograms: GHS06,GHS08
• Signal Word: Danger
• Hazard Statements: H331,H341
• Precautionary Statements: P202 - P261 - P271 - P280 - P304 + P340 + P311 - P308 + P313
• Hazard Classifications: Acute Tox. 3 Inhalation - Muta. 2
• Storage Class Code: 6.1D - Non-combustible acute toxic Cat.3 / toxic hazardous materials or hazardous materials causing chronic effects
• WGK: nwg
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves