Talk:Coomassie brilliant blue

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This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Azaman4716, Vikslick1995. Peer reviewers: Vikslick1995.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 18:26, 16 January 2022 (UTC)

Untitled

Edit: Kumasi is not near the ocean.

Protein Concentration and Molecular Weight

Coomassie Blue does not bind in identical stoichiometric proportions depending on the protein. The Dye binds to Arginine and aromatic amino acids so depending on the protein's amino acid composition, the same absorbance can reflect a different concentration depending on the protein. If one has a purified protein sample and one knows the amino acid sequence of that protein then it is indeed possible to get the concentration from Lambert-Beer's Law. In other cases however (Like in whole cell protein quantification), a protein standard must be selected. That is, a purified protein of known concentrations to which Coomassie Blue responds to in the same way as your sample protein. The two most common protein standards are BSA and Gamma-Globulin. The later is preffered when one is trying to asses the concentration of a sample which contains many proteins.

There seems to be some confusion here between Brilliant Blue G (used for the Bradford method) and Brilliant Blue R (used for staining gels).

Also, the dyes as used for these methods are anything but pure compounds. That is one reason why it is probably inadvisable to presume a certain extinction coefficient for binding to proteins, since the composition of the dye may not be constant, and the absorption change probably reflects a collection of different dye-binding processes. The Bradford method should probably always be used with a standard. In situations where it is important to know the true concentration of the protein accurately, some other method should be used. 83.65.178.205 15:04, 21 January 2007 (UTC)

Toxicity

A section on toxicity would be useful. -- stillnotelf is invisible 19:44, 18 December 2006 (UTC)

-I agree. Is this a myth or does it have something to it? —Preceding unsigned comment added by 213.236.242.126 (talk) 02:48, 15 August 2009 (UTC)

SMILES formula

CCOc1ccc(Nc2ccc(cc2)C(c3ccc(cc3C)C(CC)Cc4cccc(OS(O)=O)c4)=C5C=CC(C=C5C)=[N+](CC)Cc6cccc(OS([O-])=O)c6)cc1

Although that's the technically correct unique SMILES, I think a better way of representing the molecule, including double bond orientation, is CCOc1ccc(cc1)Nc2ccc(cc2)C(c3ccc(cc3C)N(CC)Cc4cccc(c4)OS(O)=O)/C5\C=C/C(C=C5C)=N(/CC)Cc6cccc(c6)OS([O-])=O

For whenever anyone gets around to creating an infobox.

71.41.210.146 02:56, 28 April 2007 (UTC)

Reference?

Does anyone have a reference for the fact that it only binds those particular amino acids? Aaadddaaammm 05:50, 1 May 2007 (UTC)

Coomassie G-250 and R-250

There are two Coomassie Brilliant Blue species. Coomassie G-250 and Coomassie R-250. Both species have different extinctions. I think this point has to be considered in the article. Best, Phillsox

Here is some information to consider including in the next revision. R-250 and G-250 differ by a methyl group. In staining protein gels, R-250 is the one used in the standard protocol, which is an aspect in which the current article is somewhat off. The standard coomassie protocol for staining SDS-PAGE gels uses R-250 with acetic acid and methanol fixative and destain. G-250, though, has gained in popularity over the past few years, however, because it is the form used in pre-mixed colloidal coomassie stain solutions which are manufactured ready-to-use by a number of suppliers (Bio-Rad, Pierce, Invitrogen, National Diagnostics, etc). Colloidal coomassie with G-250 provides increased sensitivity over the standard method, and colloidal staining can be safer as well. In the most popular formulations of colloidal G-250 stains, for example (Invitrogen Simply Blue Safestain, Bio-Rad Bio-Safe, National Diagnostics ProtoBlue Safe), citric acid and ethanol replace more hazardous acetic acid and methanol which are used in the standard method. Such stain solutions may be sink disposed. Another thing that you might want to mention is that before colloidal coomassie staining became widely accepted, G-250 was mainly important because the G-250 dye becomes colorless below pH 2-3. G-250 regains color on protein binding, though, and this is the property of the G-250 dye used in the Bradford Protein Assay.Wisebridge 15:22, 21 September 2007 (UTC)Wisebridge

Wrong data

The molecular formula, the molecular mass and the cas-number are wrong!! I will fix it tomorrow. Best, Phillsox.

i think it's fixed now. Roadnottaken 23:27, 5 July 2007 (UTC)

Okay. Thanks, Phillsox

I don't see any reason why this structure should be positively charged, unless the picture is wrong. Rosen643 (talk) 14:59, 23 July 2009 (UTC)

SPAMMING EXTERNAL LINKS

A lot of people spamming the wikipedia. www.westernblotting.org and biologicalworld.com for example has spammed the following pages:

• en.wikipedia.org/wiki/Gel_electrophoresis
• en.wikipedia.org/wiki/Cell_membrane
• en.wikipedia.org/wiki/Coomassie
• en.wikipedia.org/wiki/Bradford_protein_assay
• en.wikipedia.org/wiki/Blot_(biology)
• en.wikipedia.org/wiki/Fluid_mosaic_model
• en.wikipedia.org/wiki/Polyacrylamide_gel_electrophoresis
• en.wikipedia.org/wiki/Slot_blot
• en.wikipedia.org/wiki/Cell-surface

And many others I got tired of pasting. For sites of very few pages, there is very little information from this site for users especially a made for adsense site. —Preceding unsigned comment added by Sciencetalks (talk • contribs) 02:25, 4 January 2008 (UTC)