pepsin


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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 ?
Complete report on Pepsin Industry providing 12 company profiles, their product information and 178 tables and figures is available at http://www.
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.
There are many advantages of the MTS method: i) Pepsin used in the MTS method (P-7012) is much cheaper than that used in the OTS method (P-7000); ii) In the OTS method, trichloroacetic can be used to suspend the protein reaction, but it exhibits high corrosion and oxidation, which could cause environmental pollution; therefore, the reagent was replaced in MTS method; and iii) Small intestine digestibility of the rumen undegradable amino acid can be determined by the MTS method, but not the OTS method.
Pepsin is a monomeric L-protein with a high percentage of acidic residues (43 out of 327) leading to a very low pH of 1.
Pepsin is an enzyme that mixes with stomach acid to break down the protein in foods.
One unit of pepsin activity was defined as the micrograms of tyrosine released at 37[degrees]C/min/mL, considering the extinction coefficient ([epsilon]280 = 1,250/M/cm).
5 +++ pH 2 + 4 +++ 6 +++ 8 +++ 10 ++ 12 +/- Enzymes Trypsin - pepsin - protease K - catalase +++ [alpha]-Amylase +++ lipase ++ Detergents/ urea ++ chemicals [beta]-mercaptoethanol ++ Nacl ++ EDTA (1%) ++ SDS (1%) ++ Tween 80 (1%) ++ Triton X100 (1%) ++ (a) All assays were conducted with Listeria monocytogenes ATCC 7644 as indicator strain.
3], and pepsin to obtain solutions with different pH values.
Ferritin measured in the blanks represents both baseline Caco-2 cell ferritin and any newly generated ferritin resulting from exogenous iron sources (such as the minimal amounts contributed as contaminants in the pepsin enzyme preparation).
b) It directly inhibits pepsin in the presence of stomach acid.
Cookie flour samples (200mg) were weighed into an Erlenmeyer flask and mixed with 35ml of porcine pepsin (1.
The bovine whey proteins alpha-lactalbumin and beta-lactoglobulin were hydrolysed with pepsin, trypsin, chymotrypsin, pancreatin, elastase or carboxypeptidase alone and in combination.