Scientist John Northrop crystallized chymotrypsin in the early 1930’s.
In the following years, other scientists contributed to the characterization of
this enzyme, and now, it is one of the most well understood proteases.
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).
An important component of
chymotrypsin is the catalytic triad. This triad consists of residues Serine
195, Histidine 57, and Aspartate 102 (Figure 2). This triad is important for
chymotrypsin activity because the residues 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.