1
: a protease of the stomach that breaks down most proteins to polypeptides
2
: a preparation containing pepsin that is obtained from the stomach especially of the hog and is used especially as a digestive aid
Examples of pepsin in a Sentence
Recent Examples on the Web
Along with pepsin and trypsin, chymotrypsin is essential for protein digestion.
—
Jillian Kubala, Health, 8 Aug. 2024
In these cases, supplementing with proteases, such as pepsin and other proteolytic enzymes needed to break down protein, can be beneficial and sometimes necessary.
—Jillian Kubala, Health, 8 Aug. 2024
Alkaline water stops pepsin from being activated when gastric acid is released in the stomach.20
What gets rid of heartburn fast?
—Elizabeth Pratt, Health, 31 Oct. 2023
Pectin is recognized as a prebiotic that is not broken down by human saliva or gastric acid and is resistant to digestive enzymes pepsin, trypsin and rennet.
—Valerie Agyeman, Good Housekeeping, 21 Mar. 2023
Even that function is carried out by proteins like pepsin.
—Nathan Ahlgren, The Conversation, 13 Jan. 2021
In 2012, a lab study showed that water with a pH of 8.8 neutralized pepsin, the enzyme that causes damage to the esophagus in people with acid reflux.
—SELF, 6 Sep. 2018
That’s because plant protein is digested mostly in the intestines, while animal protein is digested in the stomach—which is also the point of production for pepsin.
—Alice Park, Time, 7 Sep. 2017
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Jillian Kubala, Health, 8 Aug. 2024
In these cases, supplementing with proteases, such as pepsin and other proteolytic enzymes needed to break down protein, can be beneficial and sometimes necessary.
—Jillian Kubala, Health, 8 Aug. 2024
Alkaline water stops pepsin from being activated when gastric acid is released in the stomach.20
What gets rid of heartburn fast?
—Elizabeth Pratt, Health, 31 Oct. 2023
Pectin is recognized as a prebiotic that is not broken down by human saliva or gastric acid and is resistant to digestive enzymes pepsin, trypsin and rennet.
—Valerie Agyeman, Good Housekeeping, 21 Mar. 2023
Even that function is carried out by proteins like pepsin.
—Nathan Ahlgren, The Conversation, 13 Jan. 2021
In 2012, a lab study showed that water with a pH of 8.8 neutralized pepsin, the enzyme that causes damage to the esophagus in people with acid reflux.
—SELF, 6 Sep. 2018
That’s because plant protein is digested mostly in the intestines, while animal protein is digested in the stomach—which is also the point of production for pepsin.
—Alice Park, Time, 7 Sep. 2017
Cite this Entry
“Pepsin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pepsin. Accessed 3 Mar. 2025.
Copy CitationKids Definition
pepsin
noun
pep·sin
ˈpep-sən 
1
: an enzyme given off by glands in the wall of the stomach that begins the digestion of most proteins
2
: a preparation of pepsin obtained especially from the stomach of the hog and used in medicine
Medical Definition
pepsin
noun
pep·sin
ˈpep-sən
1
: 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
2
: a preparation containing pepsin obtained as a powder or scales from the stomach especially of the hog and used especially as a digestant
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