pepsinë

Pepsin is a digestive enzyme that is a key component of gastric juice. Its primary function is to break down proteins into smaller peptides. This process is crucial for efficient protein absorption in the small intestine. Pepsin is a protease, meaning it specifically targets and cleaves peptide bonds within protein molecules.

This enzyme is produced in the stomach by chief cells, which secrete pepsinogen. Pepsinogen is an inactive precursor that is converted into active pepsin in the highly acidic environment of the stomach. The acidity, typically a pH between 1.5 and 3.5, is maintained by hydrochloric acid secreted by parietal cells. This low pH not only activates pepsinogen but also denatures proteins, making them more accessible to enzymatic digestion.

Pepsin functions optimally within this acidic range. Once food leaves the stomach and enters the more alkaline environment of the small intestine, pepsin becomes inactive. The breakdown of proteins continues in the small intestine with the help of other proteases secreted by the pancreas. Pepsin plays a vital role in the initial stages of protein digestion, contributing significantly to the overall nutritional uptake from ingested food.