noun \ˈpep-sən\

Definition of PEPSIN

:  a protease of the stomach that breaks down most proteins to polypeptides
:  a preparation containing pepsin that is obtained from the stomach especially of the hog and is used especially as a digestive aid

Origin of PEPSIN

German, from Greek pepsis digestion, from pessein
First Known Use: circa 1844


noun \ˈpep-sən\   (Medical Dictionary)

Medical Definition of PEPSIN

: a crystallizable protease that in an acid medium digests most proteins to polypeptides (as by dissolving coagulated egg albumin or causing casein to precipitate from skim milk), that is secreted by glands in the mucous membrane of the stomach of higher animals, and that in combination with dilute hydrochloric acid is the chief active principle of gastric juice
: a preparation containing pepsin obtained as a powder or scales from the stomach especially of the hog and used especially as a digestant


noun    (Concise Encyclopedia)

Powerful enzyme in gastric juice (see stomach) that partially digests proteins in food. Glands in the stomach lining make pepsinogen, a zymogen (enzyme precursor) converted to pepsin by the hydrochloric acid in gastric juice. Pepsin is active only in the acid environment of the stomach (pH 1.5–2.5 or less); it is ineffective in the intestine (pH 7, neutral). It is used commercially in some cheese making, in the leather industry to remove hair and residual tissue from hides, and in the recovery of silver from discarded photographic films by digesting the gelatin layer that holds the silver.


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