Hi Jim,
>1.) What are the references for this procedure?
We've been using the silver-removing procedure presented by F. Gharahdaghi
for about a year. By comparing the MALDI spectra of an identical sample
where silver was not removed, it is clear that it is worth the 30 minutes
extra! This is probably more useful for really weak samples. Should mention
that I have not been using colloidal silver, but the "Shevchenko-modified"
procedure.
You'll find the protocol in Gharahdaghi et al., Electrophoresis 20, 601-605
(1999).
>2.) Will it work on the sample after digestion?
Haven't tried, but I can guess that the peptides you want to analyze elute
and disappear from the gel pieces during washing unless you keep all
liquids and pass them over a tiny RPC (i e ZipTip)
>3.) What are the best references dealing with stains to avoid in gel
digests destined for MALDI?
Don't know of a ref, but silver and Coomassie are safe, and probably many
other procedures. (Somebody suggested at this forum that the best "stain"
is not to stain!!)
Regards /Ulf
Ulf Hellman, Ph. D.
Prof.
Ludwig Institute for Cancer Research
Box 595
SE-751 24 Uppsala
Sweden
Phone +46 18 160423
Fax +46 18 160420
E-mail "ulf.hellman@licr.uu.se"
alt. "cykeldoktorn@hotmail.com"
Private fax +46 18 480 2969
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