Where does the chemical digestion of proteins begin?

The chemical digestion of proteins begins in the stomach due to the presence of gastric juices, which contain hydrochloric acid and the enzyme pepsin. When food enters the stomach, the acidic environment helps to denature the proteins, unraveling their complex structures. This denaturation is essential because it allows pepsin to access the peptide bonds within the proteins and break them down into smaller peptides.

Pepsin is activated from its inactive form, pepsinogen, when it comes into contact with the stomach's acidic environment. This process is crucial for the initial breakdown of proteins, enabling further digestion to occur in the small intestine where additional enzymes will continue the process. Understanding this role of the stomach emphasizes the importance of its acidic environment and enzymatic activity in the digestive process.