Coomassie

From Wikipedia, the free encyclopedia

Coomassie
Other names	Coomassie Brilliant Blue G-250
Identifiers
CAS number	6104-58-1
PubChem	6333920
SMILES	CCN(CC1=CC(=CC=C1)S(=O) (=O)O)C2=CC(=C(C=C2)C(=C3C=CC(=[N+] (CC)CC4=CC(=CC=C4)S(=O)(=O)O)C=C3C) C5=CC=C(C=C5)NC6=CC=C(C=C6)OCC)C
Properties
Molecular formula	C47H50N3O7S2+
Molar mass	833.048
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Coomassie dyes (also known as Coomassie Brilliant Dyes) are a family of dyes commonly used to stain proteins in sodium dodecyl sulfate and blue native polyacrylamide gel electrophoresis (SDS-PAGE and BN-PAGE, respectively) gels. The gels are soaked in dye and excess stain is then eluted with a solvent ("destaining"). This treatment allows the visualization of protein bands. The gel usually contains a set of molecular weight marker (proteins of pre-determined weight) so that protein molecular weight can be estimated in an unknown solution during the visualization.

Alternatively, Coomassie may be added to undenatured protein in PAGE in place of SDS, in a technique called BN-PAGE; both SDS and CBB have the effect of imparting a net negative charge upon the proteins. Without the Coomassie, the technique is known as CN-PAGE (colorless native), and will only separate negatively-charged proteins.

Contents 1 Variations 2 Medical Uses 3 Laboratory usage 4 References 5 External links

[edit] Variations

The original Coomassie dye was developed as a wool dye and named to commemorate the 1896 British occupation of Coommassie (now Kumasi) in Ghana. The first of the Coomassie series was Coommassie Blue R-250 ("R" standing for "reddish" and "250" being the dye strength indicator). Coommassie Blue G-250 ("G" for "greenish") and Coomassie Violet R-150 later followed. The most commonly used dyes in the laboratory for staining PAGE gels are Coomassie Blue R-250 and G-250. Although G-250 is more sensitive, R-250 affords better resolution, and is often used instead. Shown at right is Coomassie Blue G-250.^[1]

[edit] Medical Uses

Brilliant Blue G (BBG) has recently been used in scientific experiments to treat spinal injuries in laboratory rats.^[2] It acts by reducing the body's natural swelling response, which can cause neurons in the area to die of metabolic stress. Testing is still in progress to determine if this treatment can be used effectively in humans, although the wide usage of blue dye in everyday life leaves no doubt about its lack of toxicity. The recent tests have administered the dye within 15 minutes of injury, but to be effective in a real-life setting, where it may take time for a patient to reach the emergency room, the treatment should be effective even when administered up to two hours after injury.The only reported side effect was that the rats turned blue.^[3][4]

[edit] Laboratory usage

Coomassie dyes are an integral component of the Bradford Method for determining protein concentration in a solution. The Coomassie dyes bind to proteins via physisorption^{[citation needed]} to arginine, the aromatic amino acids, and histidine. When Coomassie Brilliant Blue G-250 binds to proteins in acid solution, it has an absorbance shift from 465 nm to 595 nm. The absorbance data can then be used in Beer's law to determine protein concentration and ultimately the actual amount of protein in a given solution.

[edit] References

[edit] External links

• BBC News - Food dye 'may ease spinal injury'