Resolving LMW proteins

Ding Ming ming at ahabs.wisc.edu
Mon Mar 28 23:39:16 EST 1994


In article <1994Mar28.180207.1 at pearl.tufts.edu>, ajayaram at pearl.tufts.edu
wrote:

> 
> Hi there,
> 
> I'm trying to run a 8 kd protein on a SDS get but I'm having some problems
> getting it to show up due to its small size.  I've tried 10, 12 and 15
> percent gels but the but the protein doesn't seem to be there ( the problem is
> obscured by the fact this protein is being made after an induction and the coli 
> proteins interfere with seeing the bottom of the lane where the 8 kd protein
> would presumably run.)  I've tried running the gels without loading dye in the
> sample buffer thinking that the dye front would obscure the 8 kD band.  This
> didn't help.  If anyone has any suggestions about resolving low molecular
> weight proteins please respond by posting in this group or emailing me
> directly.  Thanks.
> 
> Arul
> ajayaram at pearl.tufts.edu

Dear Arul,

You should be able to see the 8kd band very easily. I am working with
proteins of 3.5 to 6.5kd and they behave very well on SDS gel. Two points
for small protein sds-page:

1)Some small proteins are not easily detected by Coomasie Brilliant Blue
and therefore, you have to use different staining methods;

2)If the protein didn't resolve well on a classic Laemmeli
system(Tris-Glycine)(usually 15% to 18% gel should work for 8Kd protein),
you should try Tricine buffer system if you havn't done that. For detailed
procedure about the tricine buffer system, please refers to Anal. Biochem.
166:368-79. Good luck!


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Ding Ming
University of Wisconsin-Madison
Telephone: (608)265-3544     Fax: (608)262-7420
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