Tobacco Etch Virus Protease is a highly site-specific cysteine protease that is found in the Tobacco Etch Virus (TEV). The optimum recognition site for this enzyme is the sequence Glu-Asn-Leu-Tyr-Phe-Gln-(Gly/Ser) [ENLYFQ(G/S)] and cleavage occurs between the Gln and Gly/Ser residues, The most commonly used sequence is ENLYFQG. The protease is used to cleave affinity tags from fusion proteins. The optimal temperature for cleavage is 30°C; also it can be used at temperature as low as 4°C. It is recommended that the cleavage for each fusion protein be optimized by varying the amount of recombinant viral TEV protease, reaction time, or incubation temperature. It can be removed by Ni²⁺ affinity resin.Recombinant Tobacco Etch Virus Protease (rTEV) contains 231 amino acids with N-terminal His tagged. A fully biologically active molecule, rTEV has a molecular mass of 28.4 kDa and is obtained by proprietary chromatographic techniques at GenScript.