An unorganized proteolytic ferment or enzyme contained in the secretory glands of the stomach. In the gastric juice it is united with dilute hydrochloric acid (0.2 per cent, approximately) and the two together constitute the active portion of the digestive fluid. It is the active agent in the gastric juice of all animals.
- A digestive enzyme found in gastric juice that catalyzes the breakdown of protein to peptides.
- A substance containing pepsin, obtained from the stomachs of hogs and calves and used as a digestive aid.