Coomassie - problems - (Jul/15/2007 )

Hi everyone,
We noticed that papain (21kDa) does not stain in electrophoresis (SDS or Native) with Coomassie and the same gels give a blur with Silver Staining. excl.gif We run the samples in different concentrations and we always have the same problem. No info on biblio. Has anybody had similar problems with the same or other proteins ??? I would appreciate ANY answer
THANKS!

-AlDente-

Have you tried to stain with Sypro Ruby? Perhaps this will work.

-biomaus-

QUOTE (biomaus @ Jul 16 2007, 09:37 AM)

Have you tried to stain with Sypro Ruby? Perhaps this will work.

No, I will. Still it is weird not to see anything with both Coomassie and Silver!
Thanks!

-AlDente-

Well, it is a strong protease. Could it be digesting itself? This would seem more likely on the native rather than the SDS gel.

-phage434-

I guess that could only happen if it is partially denatured... or not ???
Thanks for the answer
Al

-AlDente-

how much papain are you loading onto the gel? it may be too little to visualize with coomassie.

it's been a long time since i used it but i don't remember having a problem visualizing papain with coomassie on sds-page.

-mdfenko-