The Protein Man's Blog | A Discussion of Protein Research

While proteases are essential in maintaining the proper function of living cells, researchers often do not welcome their presence in their protein samples. Why would they when the mere presence of these enzymes jeopardizes the integrity of their samples and puts them one step closer to imminent degradation? No researcher would be happy knowing that there are proteases in their samples, just waiting to chew up on their precious protein, especially if their target protein is low in abundance.

When you lyse cells, either through physical disruption or by adding detergents, you also release a variety of other proteins (proteases) that are potentially harmful to your target protein. These proteases can cleave the peptide bonds between the amino acids of polypeptide chains and leave you with multiple short peptide fragments. When this happens, you will end up getting erroneous results from your experiments (western blotting, reporter gene analysis, protein interaction or activity assays).