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trypsin, enzyme that acts to degrade protein; it is often referred to as a proteolytic enzyme, or proteinase. Trypsin is one of the three principal digestive proteinases, the other two being pepsin and chymotrypsin. In the digestive process, trypsin acts with the other proteinases to break down dietary protein molecules to their component peptides and amino acids. Trypsin continues the process of digestion (begun in the stomach) in the small intestine where a slightly alkaline environment (about pH 8) promotes its maximal enzymatic activity. Trypsin, produced in an inactive form by the pancreas, is remarkably similar in chemical composition and in structure to the other chief pancreatic proteinase, chymotrypsin. Both enzymes also appear to have similar mechanisms of action; residues of histidine and serine are found in the active sites of both. The chief difference between the two molecules seems to be in their specificity, that is, each is active only against the peptide bonds in protein molecules that have carboxyl groups donated by certain amino acids. For trypsin these amino acids are arginine and lysine, for chymotrypsin they are tyrosine, phenylalanine, tryptophan, methionine, and leucine. Trypsin is the most discriminating of all the proteolytic enzymes in terms of the restricted number of chemical bonds that it will attack. Good use of this fact has been made by chemists interested in the determination of the amino acid sequence of proteins; trypsin is widely employed as a reagent for the orderly and unambiguous cleavage of such molecules.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an enzyme of the hydrolase class that cleaves peptides and proteins and also acts as an esterase—that is, it has the capacity to hydrolyze esters.

Trypsin is synthesized in the pancreas as the inactive precursor (proenzyme) trypsinogen. Samples of the trypsin of a number of animals have been obtained in crystalline form; the first crystalline trypsin was obtained in 1932. The bovine trypsin molecule, with a molecular weight of about 24,000, consists of 223 amino acid residues, which form one polypeptide chain, and contains six disulfide bonds. Its isoelectric point is at pH 10.8, and its optimum catalytic activity is at pH 7.8–8.0. The tertiary structure of trypsin was determined using X-ray diffraction analysis. Trypsin is a serine protease; it contains residues of serine and histidine at its active site. It readily undergoes autolysis, which leads to the contamination of trypsin preparations by inactive products (commercially prepared trypsin contains up to 50 percent inactive impurities). High-purity trypsin preparations are obtained chro-matographically.

Trypsin is capable of converting all the proenzymes of the pancreas (trypsinogen, chymotrypsinogen, and procarboxypeptidase), as well as phospholipase, into active enzymes, and therefore it occupies a key position in the system of digestive enzymes. It is highly specific, selectively hydrolyzing peptide bonds formed by the basic amino acids lysine and arginine. This property permits the broad use of trypsin in the study of the primary structure of insulin, ribonuclease, and other proteins. The activity of trypsin is inhibited by organophosphorus compounds and some metals, as well as by a number of macromolecular protein substances, or trypsin inhibitors, which are present in the tissues of animals, plants, and microorganisms. Ca2+, Mg2+, Ba2+, Sr2+, and Mn2+ ions enhance the hydrolytic activity of trypsin. Enzymes similar to mammalian trypsin have been found in representatives of other classes of vertebrates, as well as in several invertebrates, microorganisms, and some higher plants. Anionic trypsins, which resemble trypsin in a number of their properties but have isoelectric points in more acid media, have been discovered in humans and a number of other mammals.

Trypsin is an anti-inflammatory agent that also acts as an an-tiedemic upon intravenous and intramuscular injection; it is capable of selective removal of tissues that have undergone necrosis. In medicine, trypsin is used for the treatment of wounds, burns, and thromboses, frequently in conjunction with other enzymes and antibiotics.


Northrop, J., M. Kunitz, and R. Herriott. Kristallicheskie fermenty. Moscow, 1950. (Translated from English.)
Mosolov, V. V. Proteolitkheskie fermenty. Moscow, 1971.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A proteolytic enzyme which catalyzes the hydrolysis of peptide linkages in proteins and partially hydrolyzed proteins; derived from trypsinogen by the action of enterokinase in intestinal juice.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Yamakawa et al., "Design of variants of the second domain of urinary trypsin inhibitor (R-020) with increased factor Xa inhibitory activity," The Journal of Biochemistry, vol.
A Trypsin Inhibitor from Tamarind Reduces Food Intake and Improves Inflammatory Status in Rats with Metabolic Syndrome regardless of weight loss.
Determination of trypsin inhibitor activity of soy products: a collaborative analysis of an improved procedure.
Takahata, "Genetic characterization of a novel Tib-derived variant of soybean Kunitz trypsin inhibitor detected in wild soybean (Glycine soja)," Genome, vol.
Effect of germination on the carbohydrates, proteins, trypsin inhibitor, amylase inhibitor and haemaggliutinin in horsegram and moth bean.
Similar to trypsin-knockdown, administration of aprotinin, a trypsin inhibitor, suppresses viral replication and up-regulation of trypsin, MMPs and cytokines as well as ATP depletion, resulting in significant improvement of cellular function.
(17), Aosasa et al stated that ulinastatin block TNF-[alpha] production by inhibiting the translation of secreted TNF-[alpha], rather than transcription of its mRNA as in other trypsin inhibitor compounds.
Effects of a urinary trypsin inhibitor on acute circulatory insufficiency after surgical operation.
In soybeans, two different protease inhibitors can be found--chymotrypsin, also called the Bowman-Birk inhibitor (BBI), and trypsin, known as the Kunitz trypsin inhibitor (KTI) (STAHLHUT; HYMOWITZ, 1983; MANDARINO, 2010).