英文字典中文字典Word104.com

The Collaborative International Dictionary of English v.0.48 (gcide)

Pepsin \Pep"sin\ (p[e^]p"s[i^]n), n. [Gr. pe`psis a cooking,
digesting, digestion, fr. pe`ptein, pe`ssein, to cook,
digest: cf. F. pepsine. Cf. {Dyspepsia}.] (Physiol. Chem.)
A proteolytic enzyme (MW 34,500) 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 degrades proteins to proteoses and
peptides, and is notable for having a very low pH optimum for
its activity. It is the active agent in the gastric juice of
all animals.
[1913 Webster PJC]

Note: As prepared from the glandular layer of pigs' or
calves' stomachs it constitutes an important article of
pharmacy.
[1913 Webster]