Proteases, also called peptidase or proteinase, are a kind of simple destructive enzymes necessary for protein catabolism and the generation of amino acids in primitive organisms by hydrolyzing peptide bonds. Proteases are likely to arise at the earliest stages of protein evolution and have been applied for multiple times. Different classes of protease usually perform the same proteolysis reaction through completely different catalytic mechanisms. Proteases can be found in a wild of sources like animalia, plantae, fungi, bacteria, archaea and viruses and they participate in many body processes including digestion, immune system function, and blood circulation.
