The Protein Purification Lab is a interactive computer simulation of protein purification. This program is extremely helpful for beginners in the art of protein purification. It gives students a chance to get beyond the details of individual techniques and get a sense of the overall process of a protein purification strategy. Users try their hand at purifying a particular enzyme (1-20) while balancing purity, yield and cost. "Protein Lab" demonstrates that there are some general guidelines in the selection of techniques for protein purification but that each protein has unique characteristics that can be exploited in order to isolate a particular enzyme. Users may download the interactive computer program for free on this website, or use an online version of the tutorial exercises.