Proteolysis's the directed degradation (digestion) of proteins by cellular enzymes called proteases or by intramolecular digestion. Purposes Proteolysis's used by the cell for several purposes. They include: Removal of N-terminal methionine residues after translation. Removal of the signal sequence of peptides after their transport through a membrane Separation of viral proteins that were translated from a polycistronic mRNA Digestion of proteins from foods as a source of amino acids Conver… (More on Proteolytic)