Protein digestion takes place in stomach and duodenum which contains certain enzymes to convert the complex protein molecules into smaller and simpler ones.
Protein digesting enzyme in the stomach is pepsin which plays a role in conversion of proteins into peptones and proteoses. Pepsin is secreted in an inactive form known as pepsinogen.
Protein digesting enzymes secreted by pancreas are trypsin and chymotrypsin which are secreted in the inactive form trypsinogen and chymotrypsinogen respectively. Trysinogen become activated in the duodenum by the enzyme enterokinase into trypsin. Trypsin acts on the proteins, proteoses and peptones to convert them to smalller peptides while chymotrypsin acts on the milk proteins.