Coomassie blue

Coomassie Blue is a type of dye commonly used in molecular biology laboratories for the staining of proteins in polyacrylamide gels. It is named after the town of Coomassie in Ghana, where the dye was originally discovered.

History

The dye was first synthesized in the late 19th century and was initially used in the textile industry. It was later adopted by molecular biologists due to its ability to bind to proteins and produce a blue color, allowing for the visualization of proteins in a gel matrix.

Chemistry

Coomassie Blue is a complex organic compound with the chemical formula C47H48N3S2O7Na. It is a member of the triphenylmethane dye family, which also includes other well-known dyes such as methylene blue and crystal violet. The dye binds to proteins through ionic and hydrophobic interactions, causing a shift in its absorption spectrum and resulting in the characteristic blue color.

Applications

The primary use of Coomassie Blue is in the staining of proteins in polyacrylamide gels, a technique known as Coomassie staining. This method is widely used in molecular biology laboratories to visualize proteins after they have been separated by polyacrylamide gel electrophoresis (PAGE). The dye is also used in the Bradford protein assay, a colorimetric assay used to quantify the total protein concentration in a sample.

Safety

While Coomassie Blue is not considered highly toxic, it can cause skin and eye irritation. Therefore, it should be handled with care in the laboratory, and appropriate safety measures should be taken.

See also

• Polyacrylamide gel electrophoresis
• Bradford protein assay
• Methylene blue
• Crystal violet