Sorry if this has already been resolved previously. I could not find any solutions to our problem in past postings.
When we run SDS-PAGE gels (tris-glycine, home made, ca 8-12% T) our proteins start resolving OK. However, after a while, high molecular bands begin to dissapear. The problem can be as severe as to end up with no bands whatsoever at the end of the run. The gels are run at 70-120 Volts and never above 70 mA; also, they do not overheat, since they are cool to the touch when dissasembled.
I think we have tried changing every obvious item: reagents (tris, glycine, acrylamide...), water, even power supply and gel apparatus. It did not help.
The problem affects both samples and standards and it is not unlike the one explained here: http://www.protocol-...osts/42427.html.
I attach a picture with gel examples. One of them was run for a very short time on purpose to show that the separation starts OK but gets ruined as time goes.
Any help will be very wellcome! We are at our wits' end.