The primary enzyme involved in the digestion of proteins is pepsin. Synthesized in the stomach, pepsin is activated from its precursor, pepsinogen, in the acidic environment of gastric juice. It breaks down proteins into smaller peptides, which are further digested by other enzymes in the small intestine. Pepsin plays a vital role in the overall digestive process, allowing the body to utilize amino acids necessary for various physiological functions. Proper protein digestion is essential for nutrient absorption, growth, and maintenance of cellular function.