Coomassie Brilliant Blue G-250 Dye

Catalog number: 20279

Thermo Scientific™  Related applications: Protein Assays and Analysis | Protein Gel Electrophoresis

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Thermo Scientific Pierce Coomassie Brilliant Blue G-250 is one of the most common forms of coomassie dye, which is a key component of various colorimetric protein gel stains.

Coomassie R-250 and G-250 dyes are two chemical forms of a disulfonated triphenylmethane compound that is commonly used as the basis of stains for detection of proteins in gel electrophoresis and Bradford-type assay reagents for protein quantitation. The R-250 (red-tinted) form lacks two methyl groups that are present in the G-250 (green-tinted) form, which is also called colloidal coomassie dye. Typically, coomassie gel stains and protein assay reagents are formulated as very acidic solutions in 25 to 50% methanol. In acidic conditions, the dye binds to proteins primarily through basic amino acids (primarily arginine, lysine and histidine), and the number of coomassie dye ligands bound to each protein molecule is approximately proportional to the number of positive charges found on the protein. Protein-binding causes the dye to change from reddish-brown to bright blue (absorption maximum equals 595 nm).

Features of Coomassie Brilliant Blue R-250 and G-250 Dyes:

Easy detection—Develops intensely colored complexes with proteins
High sensitivity—Can determine as little as 0.5 µg/cm2 of protein present in a gel matrix
Reversible staining—Anion of Coomassie Brilliant Blue formed in the acidic staining medium combines with the protonated amino groups of proteins by electrostatic interaction; resulting complex is reversible under the proper conditions
Differentiation between bound and unbound dye—When dissolved in 0.01M citrate buffer at pH 3.0, has an absorption maximum at 555nm; protein-dye complex is characterized by a peak slightly broader than that of the free dye with a maximum at 549 nm

Related Products
Coomassie Brilliant Blue R-250 Dye
For Research Use Only. Not for use in diagnostic procedures.


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Target Molecule: Protein
Label or Dye: Coomassie
Detection Method: Colorimetric
Detection Location: In-Gel Detection, In-Solution Detection, In-Blot Detection
Product Size: 50 g

Contents & storage

Store at room temperature.


Manuals & protocols

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