Digestive Proteases: Roles in the Human Alimentary Tract

Digestive proteases are distributed throughout the alimentary tract but are abundant in the stomach and small intestine. Different segments of the alimentary tract have characteristic functions, conditions and proteolytic enzymes. The aspartic endopeptidase pepsin is predominant in the stomach whereas the serine endopeptidases trypsin and chymotrypsin are abundant in the small intestine. Proteolysis releases small peptides and amino acids that are absorbed. Digestion is essentially complete before effluent from the small intestine enters the large intestine. In the large intestine residual products of protein digestion are detoxified, water and salts reclaimed, and indigestible material and microorganisms are eliminated as feces.