An overview of enzymatic reagents for the removal of affinity tags

► I review enzymes commonly used to remove affinity tags. ► Both endoproteases and exoproteases are covered. ► The specificity and biochemical properties of proteases are discussed. Although they are often exploited to facilitate the expression and purification of recombinant proteins, every affinity tag, whether large or small, has the potential to interfere with the structure and function of its fusion partner. For this reason, reliable methods for removing affinity tags are needed. Only enzymes have the requisite specificity to be generally useful reagents for this purpose. In this review, the advantages and disadvantages of some commonly used endo- and exoproteases are discussed in light of the latest information.