Cards (5)

  • peptidases or proteases are enzymes which breakdown proteins in a series of hydrolysis reactions
  • Endopeptidases:
    • hydrolyse peptide bonds within a large protein to create smaller polypeptide chains
    • endopeptidases create more terminal ends for exopeptidases to then work on
  • Exopeptidases:
    • hydrolyse terminal peptide bonds ( between amino acids on the ends of a polypeptide chain )
    • this removes individual amino acids and create smaller polypeptide chains
  • Dipeptidases:
    • a type of exopeptidase
    • located on the membrane of epithelial cells lining on the small intestine
    • work on dipeptides to hydrolyse the peptide bond holding them together
    • this creates two single amino acids which can be transported through membrane into epithelial cells
  • In the stomach:
    1. whole proteins are chewed and swallowed into the stomach
    2. hydrochloric acid denatures proteins to reveal the polypeptide chain
    3. enzymatic digestion by pepsin forms shorter polypeptide
    in the small intestine:
    4. trypsin and other proteases continue enzymatic digestion forming tripeptides, dipeptides and amino acids
    5. in enterocytes these peptides are broken down further into amino acids which are absorbed into the blood