Ampholytes in Isoelectric Focusing

[8181992]

Hi,

 

I have just started my first Biochem course. I'm a bit confused about isoelectric focusing.

 

So the ampholytes are added to the gel, and then the electric field is applied. If an ampholyte is singly positively charged, it moves toward the cathode...as if moves toward the cathode it will lose a proton, and because it is no longer charged it will be immobilized. Does that proton (or whatever solution is carrying the proton) move then toward the anode? Is this how the pH is established? I'm a bit confused as to how the ampholytes set up a pH when there is no proton gradient to start with.