Immunohistochemistry is usually positive for trypsin, chymotrypsin and lipase. The pancreas secretes the precursors of a number of proteases such as trypsin and chymotrypsin. TPCK is an irreversible inhibitor of chymotrypsin. This approach was first applied to the hydrolysis reaction catalysed by chymotrypsin. A short animation showing the mechanism of chymotrypsin is linked here. Chymotrypsin, trypsin and Diclofenac are also recommended. It inhibits proteases like chymotrypsin, kallikrein, plasmin, thrombin, and trypsin. The mode of action of chymotrypsin explains this as hydrolysis takes place in two steps. PSMB5 is part of the 20S proteasome complex and has enzymatic activity similar to chymotrypsin. The mechanism of chymotrypsin can be divided into two phases. Additionally, trypsin inhibitor partially interferes with chymotrypsin function. All members of the chymotrypsin family of serine proteases have very similar structures. Smegma contains cathepsin B, lysozymes, chymotrypsin, neutrophil elastase and cytokines, which aid the immune system. Chymotrypsinogen is the inactive form of chymotrypsin and has similar functions as trypsin. The enzymes trypsin and chymotrypsin were first purified in the 1930s.