We consider the dynamics of polyampholytes (PAs, polymers containing positive and negative charges) in a fixed network (gel), Under the influence of an external electrical field a PA undergoes a biased reptation; the electrophoretic mobility of the chain depends crucially on the given charge distribution. This effect, which does not occur for equally charged polymers (polyelectrolytes, e.g., DNA) leads to an effective separation of PAs according to their charge distribution-even for PAs of the same length and the same overall charge.