Coomassie staining

[Marcus Schmidt]

User asavitt at sunysb.edu wrote under "Coomassie staining:"

[...]
>                   What I would like to know is this:  what about a
> protein makes it Coomassie stainable?

I must admit I forgot. A certian Amino acid I recall, but I completely  
forgot which one. Look it up in the "Cooper".

>                                       Are some proteins less susceptible
> to Coomassie staining than others? If so, why?

Yes!

That is so because most Tests, including Coomassie, only detect a certain  
amino acid, most of the Time even only its prosthetic proup. As the  
relative contents of each amino acid varies from protein to protein, there  
are _great_ differences. Thus you always have to include the protein you  
relate your measurements to, as You should know. Usually this is Bovine  
Serum Albumine (BSA).

Any of those staining tests used in biochemistry only gives you relative
measurements. To determine the absolute Protein content you have to  
purificate the cell contents and determine protein dry weight.


Bye
        Marcus Schmidt


"I wanna be in anarchy!" (J.Rotten)

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