pepsin


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

pepsin

 [pep´sin]
a proteolytic enzyme that is the principal digestive component of gastric juice. It acts as a catalyst in the chemical breakdown of protein to form a mixture of polypeptides; it is formed from pepsinogen in the presence of acid or, autocatalytically, in the presence of pepsin itself. Pepsin also has milk-clotting action similar to that of rennin and thereby facilitates the digestion of milk protein.

pep·sin

(pep'sin),
A group of closely related aspartic proteinases. Pepsin A is the principal digestive enzyme of gastric juice, formed from pepsinogen; it hydrolyzes peptide bonds at low pH values (is alkali-labile), preferably adjacent to phenylalanyl and leucyl residues, thus reducing proteins to smaller molecules (referred to as proteoses and peptones); pepsin B (gelatinase) is similar to pepsin A, but formed from porcine pepsinogen B and has a more restricted specificity; pepsin C (gastricsin is human pepsin C) is also similar to pepsin A, and structurally related to it, having a more restricted specificity.
[G. pepsis, digestion]

pepsin

/pep·sin/ (pep´sin) the proteolytic enzyme of gastric juice which catalyzes the hydrolysis of native or denatured proteins to form a mixture of polypeptides; it is formed from pepsinogen in the presence of acid or, autocatalytically, in the presence of pepsin.

pepsin

also

pepsine

(pĕp′sĭn)
n.
1. A digestive enzyme found in gastric juice that catalyzes the breakdown of protein to peptides.
2. A substance containing pepsin, obtained from the stomachs of hogs and calves and used as a digestive aid.

pepsin

[pep′sin]
Etymology: Gk, pepsis, digestion
an enzyme secreted in the stomach that catalyzes the hydrolysis of protein. Preparations of pepsin obtained from pork and beef stomachs are sometimes used as digestive aids. See also enzyme, hydrolysis.

pepsin

A generic term for any of the gastric proteases that are released by gastric chief cells as proenzymes (pepsinogen).

pep·sin

(pep'sin)
The enzyme produced by the stomach for the digestion of protein.
[G. pepsis, digestion]

pepsin

A digestive ENZYME whose precursor PEPSINOGEN is secreted by cells in the stomach lining. Pepsin breaks down protein to PEPTIDES. See also PEPTIDASE.

pepsin

an enzyme secreted in the inactive form PEPSINOGEN by chief or peptic cells in the gastric pits of the stomach of vertebrates, and which breaks down proteins in acid solution into short polypeptide chains which are subsequently broken down further by PEPTIDASES.

pepsin

a proteolytic enzyme that is the principal digestive component of gastric juice. It acts as a catalyst in the chemical breakdown of protein to form a mixture of polypeptides; it is formed from pepsinogen in the presence of acid or, autocatalytically, in the presence of pepsin itself. Pepsin also has milk-clotting action similar to that of rennin and thereby facilitates the digestion of milk protein.

pepsin barrier
the gastric mucosal mechanism which prevents rediffusion of hydrochloric acid back into gastric tissues; includes an electrical resistance, mucus, plus bicarbonate ions trapped in the mucus, endogenous prostaglandins.
References in periodicals archive ?
BSH 1b, BSH 3a, BIP 4a, BIP lb and BRR 3a were found to be fully or partially inactivated by pepsin that was a proteolytic enzyme (Table l).
Influence of chemical modification of whey protein conformation on hydrolysis with pepsin and trypsin.
In this study, proteins of different molecular weights such as BSA (69 kDa), EA (45 kDa), pepsin (35 kDa), and trypsin (20 kDa) were chosen for the estimation of MWCO.
acid and alkaline phosphatases and leucine aminopeptidase) present from hatching, joined to appearance of pepsin activity between 20-25 days after hatching, considered as onset of juvenile period (Galaviz et al, 2012; Moguel-Hernandez et al, 2013).
The degradation of the samples was studied by exposing the materials to cyanogen bromide, pepsin and papain solution.
Later, she did her PhD at the University of Cambridge under the guidance of John Desmond Bernal, where she discovered the potential of X-ray crystallography to determine the structure of proteins, while working with Bernal on the technique's first application to analysis of a biological substance, pepsin.
In contrast, pepsin activity in the gastric juice of starved animals was the greatest.
When an ulcer occurs in the lining of the stomach, where the body produces hydrochloric acid and pepsin, or in the duodenum, it is called a "peptic ulcer", and when a peptic ulcer is located in the duodenum, which is the first part of small intestine, it is called a "duodenal ulcer".
It is known that hog pepsinogen is stable in a mild alkaline medium in which hog pepsin is unstable.
The product joins an expanding line of FISH slide processing products from the company, including FISH Wash Buffers, CytoZyme Stabilized Pepsin and CytoBond Removable Coverslip Sealant.
1] and its homologs, Section II-aspartic peptidases: pepsin, nepenthesin and their homologs, Section III-glutamic peptidases: aspergilloglutamic peptidase and its homologs and Section IV-serine-carboxyl peptidases: physarolisins I and II and their homologs.