You decided that you would like to make a recombinant ERalpha that has an epitope tag that can be removed by using a protease and this can be accomplished by inserting a protease cleavage site between the epitope tag and the ERalpha protein. Using the ERalpha protein sequence below and "Peptide Cutter" Bioinformatic tool found on ExPASy, please indicate ONE specific protease cleavage site that you can use for making the desired recombinant epitope-tagged ERalpha protein.