Mechanical digestion of protein beings in the in the mouth and continues in the stomach and the small intestine.

and chemical digestion of protein beings in the stomach and ends in the small intestine . the body recycles amino acids to make more proteins.

and in the animals the initial digestion of proteins take place in the stomach.

The initial digestion of proteins takes place in the stomach.

Stomach:
- The stomach is a muscular organ located in the upper abdomen, which plays a crucial role in the digestion of proteins.
- It secretes gastric juice, which contains hydrochloric acid and enzymes such as pepsinogen.
- The hydrochloric acid creates an acidic environment in the stomach, which is necessary for the activation of pepsinogen into pepsin, an enzyme that breaks down proteins.
- Pepsin breaks down proteins into smaller peptides by breaking the peptide bonds between amino acids.

Enzymatic action in the stomach:
- When we consume protein-rich food, it enters the stomach and mixes with gastric juice.
- The hydrochloric acid denatures the proteins, unfolding their complex structures and exposing the peptide bonds.
- Pepsinogen, secreted by the gastric glands, is activated by the acidic environment and converts into pepsin.
- Pepsin then acts on the denatured proteins and breaks them down into smaller peptide chains.
- The partially digested proteins, along with other gastric secretions, form a thick, semi-liquid mixture called chyme.

Small Intestine:
- The chyme moves from the stomach into the small intestine, where further digestion and absorption of nutrients occur.
- The small intestine receives secretions from the liver and pancreas to aid in the digestion process.
- The pancreas secretes pancreatic juice, which contains enzymes like trypsin, chymotrypsin, and carboxypeptidase.
- These enzymes act on the peptides, breaking them down into smaller peptides and individual amino acids.
- The small intestine also produces its own enzymes, such as peptidases, which further break down the smaller peptides into individual amino acids.
- The final products of protein digestion, i.e., amino acids, are then absorbed into the bloodstream through the lining of the small intestine.

Summary:
- The initial digestion of proteins takes place in the stomach, where pepsin breaks down proteins into smaller peptides.
- The process continues in the small intestine with the help of pancreatic enzymes and peptidases, eventually resulting in the breakdown of proteins into individual amino acids, which are then absorbed into the bloodstream.