Fast and Cheap Protein Purification : 9783639154436 : 28 Jun 2009 : Two naturally produced in vivo affinity resin substitutes have been combined with a self-cleaving tag to develop two novel affinity-based purification technologies. The first resin alternative is polyhydroxybutyrate (PHB) granules and the second is elastin-like polypeptides (ELP). An engineered tripartite protein fusion is expressed in E. coli and purified through simple centrifugation. The intein self-cleaving tag then releases the target protein with a mild pH shift. The two systems have been successfully used at laboratory scale to purify more than a dozen proteins varying in size, complexity and activity, demonstrating the proof of principle, high purity and yield attainable. Hence, the cost associated with purification of recombinant proteins is reduced significantly to effectively that of just the culture medium. It is expected that this combination of improved economics and simplicity will constitute a signifi