It aims to guide students through a simulation of some of the more commonly-used protein separation techniques and to let them experiment with the simulation. It starts off by letting the user examine how a simple mixture of proteins behaves during gel filtration and ion-exchange chromatography and then goes on to allow the design and testing of full purification protocols using more complex mixtures of proteins. It is assumed that students are familiar with the theoretical background to the most common separation techniques, enzyme assays etc. and that they understand the concept of the isoelectric point of proteins. Bear in mind that this is a laboratory simulation.