Chymotrypsinogen must be inactive until it gets to the digestive tract, in order to prevent damage to the pancreas or any other organs. It is activated by another enzyme called
trypsin. The active form is called π-chymotrypsin and is used to create α-chymotrypsin. Trypsin cleaves the peptide bond in chymotrypsinogen between
arginine-15 and
isoleucine-16. This creates two peptides within the π-chymotrypsin molecule, held together by a disulfide bond. One π-chymotrypsin acts on another by breaking a
leucine and
serine peptide bond. The activated π-chymotrypsin reacts with other π-chymotrypsin molecules to cleave and remove two dipeptides: serine-14–arginine-15 and threonine-147–asparagine-148. This reaction produces α-chymotrypsin. The yield of α-chymotrypsin can be affected by inhibitors such as hydrocinnate and also by pH, temperature and calcium chloride. The activation process can be studied using fluorescence probe 2-p-toluidinylnaphthalene-6-sulfonate (TNS). TNS forms covalent bonds with chymotrypsinogen and as the bonds break to form chymotrypsin in the presence of trypsin, the fluorescence increases. ==References==