Scientist John Northrop crystallized many enzymes and proteins in the
early twentieth century. One important enzyme he crystallized was chymotrypsin.
In the following years after his crystallization, other scientists contributed
to the characterization of this enzyme, and now, it is one of the most well
Chymotrypsin is a digestive enzyme produced by the pancreas, and it is
responsible for the breakdown of proteins and polypeptides. Specifically, it is
an endopeptidase, and breaks bonds within a polypeptide. Without chymotrypsin,
proper food digestion cannot occur. Chymotrypsin consists of two chains, and is
made up of 245 amino acids (Figure 1).
The catalytic triad is an important component of chymotrypsin. This
triad consists of residues Serine 195, Histidine 57, and Aspartate 102 (Figure
2). Together, they work to stabilize the enzyme and promote catalysis. The
aspartate and histidine are bound to each other by hydrogen bonds, allowing
histidine to work as a base for serine. Serine can then become a nucleophile to
catalyze the breakdown of proteins