How is peptide bond broken?

Peptide bonds are easily broken through the process of hydrolysis. The hydrolysis of peptide bonds in water releases 8-16 kJ/mol of Gibbs energy. It is a slow process, with a half life at 25 degrees Celsius of between 350 and 600 years per bond. In addition to hydrolysis, peptide bonds can be broken by different types of enzymes like digestive enzymes or bacterial enzymes. Sortases have transpeptidase properties and have the ability to site-specifically break peptide bonds and create a new bond with a nucleophile; this is useful for protein engineering. Proteases are digestive enzymes that target alpha peptide cleavage bonds at the ideal temperature and pH. These enzymes can either break specific peptide bonds or completely break a peptide down to amino acids. Peptide bonds can also be broken by a long-term exposure to a strong acid or base at high temperatures. They cannot be broken by simply exposing them to heating or high salt concentration.