Resolving two proteins of very close size

Hi all,

I am trying to express a protein as a fusion product of Maltose Binding Protein. My protein is of just 13KDa. When I run pure MBP and the fused product in the SDS PAGE, they appear almost at the same level. I want to resolve them more. Can anybody have any suggestions of what % of gel needs to be used or anything? MBP's molecular weight is 42.5 KDa and the fused product is 55.5KDa.

Thanks for any reply.

Sam

Hi Sam's Lab,

If you run the sample on a 10% gel longer than you usually run so that ~35kDa region hits the bottom of the gel, you shoule be able to get those two to separate.

Good luck

 HI Sam

U have several options
1. Run a 12% gel 
2. Run a 10% gel with 3% C
3. Run a gel with SDS Tricine instead of SDS glycine

Thanks Pippuri. This helped a lot.