Single-Step Non-Chromatographic Purification of Recombinant Mammalian Proteins Using a Split Intein ELP Tag System

Glycoprotein therapeutics are currently used by large patient populations and generate significant revenue for the biopharmaceutical industry. These therapeutic proteins are currently purified at industrial scale using individualized processes involving multiple chromatographic steps. In the absence of a viable affinity platform method, the required chromatographic steps are difficult to develop and inevitably lead to significant yield losses. Further, during preclinical development, there is a need for reliable platform technologies capable of performing high-throughput screening for biologic candidates. Although affinity tags can provide a solution to some of these challenges, they require specific affinity resins, and the tag itself can interfere with the target protein characteristics. Fusion protein systems consisting of elastin-like polypeptide (ELP) and self-cleaving split inteins such as Npu DnaE can serve as potential non-chromatographic platform technologies for the single-step purification of tagless glycoproteins expressed in mammalian cells. In this chapter, we demonstrate the use of this technology to obtain highly purified anti-ErbB2 ML39 single-chain variable fragment (scFv) expressed from Expi293F suspension cells.