Digestion of proteins into smaller units (tripeptides, dipeptides, amino acids) occurs in both, the stomach and the small intestine by the enzymes peptidases. Enzymes involved in protein digestion are:
• Pepsin-secreted from gastric chief cells of stomach; acts on low pH that is achieved with HCl in stomach
• Trypsin-secreted from pancreas; protease that cleaves proteins at the carboxyl side of the amino acids
• Chymotrypsin-secreted by the pancreas, cleaves peptide amide bonds at N-terminal
• Elastase-secreted from the pancreas
• Carboxypeptidase- secreted from the pancreas, hydrolyzes a peptide bond at the C-terminal of a protein.