is a protease, which is an enzyme that catalyzes the cleavage of amino acids at the carboxyl side. This study utilized a bovine pancreatic trypsin inhibitor (BTPI) in order to study the structure of bovine α-chymotrypsin homodimer.[1]
Structural Highlights and Function
Chymotrypsinogen is the inactive form of chymotrypsin. Before chymotrypsinogen becomes α-chymotrypsin, trypsin cleaves the polypeptides at three locations: between residues 14-15, 146-147, and 148-149. The resulting α-chymotrypsin is composed of (residues 1-13 shown in maroon, 16-146 shown in blue, and 149-245 shown in gold). The active site of chymotrypsin consists of a (Ser 195, His 57, Asp 102), which are highlighted in blue. The of the bovine α-chymotrypsin is highlighted in yellow.
The S1 binding pocket is responsible for stabilizing the substrate before cleaving. The S1 pocket is mainly hydrophobic and preferentially binds to large, nonpolar amino acids, which includes tyrosine, tryptophan, and phenylalanine.
Chymotrypsin and other serine protease enzymes catalyzes the cleavage of amino acids. Both the active site and S1 pocket can be seen . The catalytic triad is highlighted in blue and the S1 pocket is highlighted in yellow.
The serine, histidine, and aspartate residues from the catalytic triad forms hydrogen bonds between each other. The structure of the binding and active site of a monomer is highlighted .
