Proteolysis is the directed degradation (
digestion) of
proteins, either by cellular
enzymes called protease
?s, or by intramolecular digestion.
Proteolysis is used by the cell for several purposes. They are:
- Removal of N-terminal? methionine? residues after translation.
- Removal of the [signal sequence]? of peptides after transport through a membrane]
- Separation of viral proteins that were translated from a monocistronic? mRNA.
- Digestion of proteins.
- Conversion of predecessor-proteins (proenzyme?s, zymogene?s, prehormone?s) into their final structure.
Examples for proteases are trypsin and chymotrypsin.