蛋白质消化

Protein digestion primarily begins in the stomach, the strong acidic environment that can disrupt the protein structure, exposing peptide bonds within a polypeptide chain.

For instance, the stomach enzyme pepsin breaks the bonds to form smaller peptide fragments, shorter chains of amino acids. As the peptides move to the duodenum, the entry of chime activates several other enzymes like trypsin, that continue to break apart the peptide bonds, creating a variety of even shorter peptides. 

The epithelial surface of the small intestine secretes several peptidases which are enzymes that break short peptide chains into individual amino acids. These amino acids are then absorbed into the bloodstream where they can be carried throughout the body to be used for protein synthesis or transported to the liver where they are used to produce energy.