This is a biological molecule that is found in our digestive system. And what trypsin basically does is it cleaves our peptide at a specific site. So at the carboxyl side of Lysine and Arginine are two basic amino acids. We also have chimotrypsin and chimotrypsin cleaves at the carboxylan of tyrosine, methionine, phenylalanine, tryptophan, and leucine. So basically, if we have some type of amino acid that contains an aromatic ring, this is our protein enzyme that cleaves it. And finally, another example is thrombin.