I'm nut sure what system you are using, but I've detected 3.5 kD peptides
on 10% SDS-Page gels before. I've used the NOVEX Nu-Page system, and had
no problems detecting it using their colloidal blue stain.
Also, considering you have three Tyr residues, have you tried fluorescence
detection instead of UV?
Hope this helps,
Lisa
> Rasmus Wendelbo Nielsen wrote:
>> > I am currently trying to purify a protein of 5 kDa, but are having
> > problems detecting the protein. As it only contains tree tyrosines and
> > no tryptophans the A280 is very low. I have tried running 18% SDS-PA
> > gels and a 15 to 25% SDS PA gradient-gels, without luck, the protein
> > probably diffuses out of the gel during staining.
> > So I am looking for other (easy) ways to detect low MW proteins. Any
> > ideas would be appreciated!
> > I have heard that adding coomassie to the running buffer instead of
> > post-staining the gels could be a solution. Anyone got experience with
> > that?
> > Thanks, Rasmus
>
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Lisa Kueltzo
Department of Pharmaceutical Chemistry
University of Kansas
(785) 864-3010
"Black Holes are where God Divided by Zero."
- Anonymous
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