Which enzyme is specifically responsible for breaking down protein into polypeptides?

Pepsin is an enzyme specifically responsible for the breakdown of proteins into smaller chains known as polypeptides. This process occurs primarily in the stomach, where pepsin is activated from its inactive form, pepsinogen, in the presence of hydrochloric acid. The acidic environment of the stomach is essential for pepsin's activity, and it serves to begin the digestion of protein, making larger protein molecules more accessible for further breakdown by other enzymes in the small intestine.

Understanding the role of pepsin highlights its significance in the digestive process, particularly for the digestion of dietary proteins, which are crucial for various bodily functions including muscle repair and growth. The digestion of proteins continues in the small intestine, where additional enzymes complete the breakdown into amino acids that can be absorbed by the body.