Protein modification and its biological role

The modifications present on a polypeptide play an important role in determining its eventual fate. Modifications, particularly proteolysis, are important in the generation of biological activity. Modifications are used to "target" particular polypeptides to specific cellular locations. Protein modification also plays a role in determining the rate of polypeptide degradation. Cells have developed elaborate systems for the modification of their proteins because these modifications serve important biological functions.