digestion of proteins

• dipeptidases = hydrolyse the bond between two amino acids of a dipeptide
• endopeptidases = hydrolyses peptide bonds between amino acids in the central region of a protein molecule, forming a series of peptide molecules
• exopeptidases = hydrolyses peptide bonds on the terminal amino acids of the peptide molecules formed by endopeptidases
• stomach

  • whole proteins are chewed and swallowed in the stomach
  • hydrochloric acid denature proteins, unfolding their 3D structure to reveal the polypeptide chain
  • enzymatic digestion by pepsin forms shorter polypeptides
• small intestine

  • trypsin, chymotrypsin and proteases continue enzymatic digestion, forming tripeptides, dipeptides and amino acids
  • in enterocytes, tripeptides and dipeptides are further broken down into amino acids
  • these are absorbed into the blood