I am trying to do a western blot to detect the levels of expression of a large protein made up of 5 subunits 140 KDa for each subuit. I am getting signal at the position of the wells, so the protein is trapped in the wells. I use a loading buffer which has Beta-mercaptoethanol, which should reduce the protein to where I can get the subusits separate into monomers but for some reason that is not happening. Please help? What can I do differently?