We've had a problem in my lab where running two SDS-PAGE gels at once has resulted in the proteins/dye in one gel migrating much faster than the other, so that we have to pull out one gel and leave the other one in for 10-20 minutes. This is really unusual -- what could be the cause of this? Thanks!
Did you use precasted gels? If it wasn't a precasted gel and you prepared both separating gels from one tube, insufficient mixing might be a cause. If you casted the gels immediatly after adding polyacrylamide or the radical initiator, you might have different amounts of acrylamide in the separating gels.
If you are using different percentage of separating gels than this is a normal situation.
Gel percentage, gel SDS percentage and the presence or absence of 2-ME all affect the mobility migrating and running time.
If you run two different percent of gels for eg one 8 % and other 10 % than the pore size of the gels would also be different, however, same current would be applied to both the gels.This will cause different migration of proteins.i.e same electric field but different pore sizes Everytime higher percent of gel will take longer time to run/ resolve because pore size is smaller.
check the input voltage devices of both the units that applied to SDS-PAGE may b it could be the reason
Hi Evan. Do not worry, sometimes when you use a gel with resolving and stacking gel. The heights of the stacking gel might make the difference, because stuff runs faster through stacking gel than resolving gel. Furthermore it also plays a role how old your gels are. Older gels tend to run faster.
I had the same problem. Two pre-cast gels that were both 4-15% gradient gels were run in the same unit right next to each other and one of them ran much faster than the other. Kind of causes an inconvenience when you have to take one gel out and run the other for longer.
If two gels are identical then there might be a leakage/inbalance at the upper chamber. After a while, if, at one side of the chamber, buffer level decreases; then it may cause interruption in current and stopping/slowing the movement at that gel.
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