Pepsin Health Dictionary

An ENZYME found in the gastric juice which digests proteins, converting them into peptides (see PEPTIDE) and AMINO ACIDS. It is used in the preparation of predigested foods (PEPTONISED FOODS), or, more frequently, taken orally after meals. Available as a white powder or liquid, it is prepared from the mucous membrane of cow, sheep, or pig stomachs.

n. an enzyme in the stomach that begins the digestion of proteins by splitting them into peptones (see peptidase). It is produced by the action of hydrochloric acid on pepsinogen, which is secreted by the gastric glands. Once made, pepsin itself can act on pepsinogen to produce more pepsin.