Name: Chymotrypsin

Synonyms: alpha-Chymotrypsin

CAS Registry Number: 9004-07-3

EINECS: 232-671-2

 

Chymotrypsin (bovine ¦Ã chymotrypsin: PDB 1AB9, EC 3.4.21.1) is a digestive enzyme that can perform proteolysis. Chymotrypsin cleaves peptides at the carboxyl side of tyrosine, tryptophan, and phenylalanine because these three amino acids contain aromatic rings, which fit into a 'hydrophobic pocket' in the enzyme. Over time, chymotrypsin also hydrolyzes other amide bonds, particularly those with leucine-donated carboxyls.

Chymotrypsin is synthesized in the pancreas by protein biosynthesis as a precursor called chymotrypsinogen that is enzymatically inactive. On cleavage by trypsin into two parts that are still connected via an S-S bond, cleaved chymotrypsinogen molecules can activate each other by removing two small peptides in a trans-proteolysis. The resulting molecule is active chymotrypsin, a three polypeptide molecule interconnected via disulfide bonds.