Which enzyme in the human body is known for digesting proteins?

Pepsin is a crucial enzyme in the human body that specifically digests proteins. It is produced in the stomach and functions optimally in the highly acidic environment created by gastric acid. This enzyme breaks down large protein molecules into smaller peptides, facilitating further digestion and nutrient absorption in the intestines.

Lactase, on the other hand, is responsible for breaking down lactose, the sugar found in milk, and does not play a role in protein digestion. Amylase is designed to digest carbohydrates, particularly starches into sugars, so it does not interact with proteins. Lysozyme has antibacterial properties and breaks down certain carbohydrates in bacterial cell walls, but it is also not involved in the digestion of proteins. Thus, pepsin's role as a specific protein-digesting enzyme in the stomach makes it the correct answer.