E1510

Ethidium bromide solution

Name: Ethidium bromide solution
Brand: SIGMA

BioReagent, 10 mg/mL in H₂O

Synonym(s):

3,8-Diamino-5-ethyl-6-phenylphenanthridinium bromide, EtBr, Homidium bromide

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About This Item

Empirical Formula (Hill Notation):

C₂₁H₂₀BrN₃

CAS Number:

1239-45-8

Molecular Weight:

394.31

Beilstein:

3642536

MDL number:

MFCD00011724

UNSPSC Code:

41105322

PubChem Substance ID:

24894418

NACRES:

NA.31

Key Documents

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grade

Molecular Biology

Quality Level

200

product line

BioReagent

concentration

10 mg/mL in H₂O

technique(s)

electrophoresis: suitable

suitability

suitable for gel electrophoresis

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

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.

Ethidium bromide solution has been used:

as a stain to visualize U937 cells to assess cell viability
to detect polymerase chain reaction products
in agarose gel electrophoresis based gel retardation assay

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.