Stomach:
* Pepsin: This enzyme, produced by the stomach lining, breaks down proteins into smaller polypeptide chains. It works best in the acidic environment of the stomach.
Small Intestine:
* Pancreatic Proteases: The pancreas secretes several enzymes, including trypsin, chymotrypsin, and carboxypeptidase. These enzymes further break down polypeptides into smaller peptides and individual amino acids.
* Brush Border Enzymes: The lining of the small intestine contains enzymes like aminopeptidase and dipeptidase. These enzymes complete the breakdown of peptides into individual amino acids, which can then be absorbed into the bloodstream.
Other Organs Involved:
While not directly involved in the chemical breakdown, other organs play a supporting role:
* Liver: Produces bile, which helps emulsify fats, allowing enzymes to access protein molecules.
* Gallbladder: Stores and releases bile into the small intestine.
In Summary:
The chemical breakdown of proteins is a multi-step process involving several organs and enzymes working together. The stomach initiates the process, while the small intestine completes it, aided by enzymes from the pancreas and the small intestine lining.
