So let's call this blue section, let's call it three B. And let's call this green section, three A because that will become important in just a moment. So this is step A of diagonal electrophoresis. What do we do in step B? Well, now in step B, once we have the separation of these four fragments, we now want to expose the sheet that contains these separated proteins to special type of chemicals. So we essentially vaporize the chemical and we expose our sheet to this chemical that essentially breaks our disulfide bond.