RE: Peptides & Coomassie R-250

Dick-van Wassenaar (Dick-van.Wassenaar@unilever.com)
Mon, 23 Aug 1999 13:44:52 +0200

As with all proteins [any] intensity of staining is dependent on the
interaction of the dye with the 'reactive' amino groups being
+ charged and hydrophobic ones in particular for Coomassie.
When such amino acids are not present, there is no staining possible and the
peptides are thus not visible!

Dick van Wassenaar
Unilever Research Vlaardingen
The Netherlands

-----Original Message-----
From: Jenny Shipway [SMTP:jennys@biols.susx.ac.uk]
Sent: Monday, August 23, 1999 12:12 PM
To: Recipients of ABRF List
Subject: Peptides & Coomassie R-250

Hello list,

I've been playing with IEF recently, but when I stain (Coomassie R-250) my
gels (Phastgel) I can only see the standards. They're present at about
50ng each, while my peptides (30aa) remain invisible even at 1000ng.

Are there any possible reasons why the dye may not be sticking to my
peptides? They're not massively exciting. Should form coiled-coils.

Alternatively, do I just need more peptide on there? The book said to use
between 60 and 2000ng. Considering the visibility of the standards, I'd
have thought I should have seen something at 1000ng.

Thanks in advance,

Jenny Shipway
Centre for Biomolecular Design and Drug Development
University of Sussex