Hi CharonY, Thanks for your reply. That is my concern too. If protein complexes break up in a denaturing gel, it should be fine since I will only see a single band that indicates A. However, if I see a high-MW band that indicates AB complex, it's gonna affect my quantification of A's decay since some A are existing in the form of AB complex. So my question is there a way to break up complex on purpose right before running the gel? In that case, I should be able to tell between B stablizing A and B binding A. Thank you