Detection of "Invisible" Proteins???

Virginia Dress Dress at
Wed Oct 26 16:26:49 EST 1994

In article <1994Oct24.191425 at>, ggordon at wrote:
 Our problem is this...this sequence contains NO AROMATIC AA's...That 
> means it can't be detected by UV-light, and therefore can't have its
> concentration determined by spectrophotometry.
  We can't really run this on SDS-PAGE and it seems
> that the Bradford assay also needs aromatics.  

> 	Scott Gordon
> 	Tufts/Sackler School of Biomedical Science 
(above message edited for brevity)

Some of the other posters have already suggested some good ideas but here's
my 2 cents worth ---
					You should be able to run it on the gel, I'm not sure Coomassie Blue
requires aromatic residues, but if it does there is still silver-staining.
					Besides the Bradford assay there is the Lowry assay, the BCA assay
get a kit from Pierce), and colloidal gold.  I'm not sure about the others
but I'm pretty sure the colloidal gold does not require aromatic residues.
		   Like others have said, try detecting at 210-214nm.
					This is reaching but if you have an antibody to the protein you could
ELISA, dot blots or western blots to detect the protein.  If you want to 
actually quantitate the protein you would need to do a competitive ELISA.  
There has already been talk in this group about quantitating Westerns, it 
would be the same for dot blots.  

Good luck,

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