Trypsin

trypsin

[′trip·sən]

(biochemistry)

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.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Trypsin

 

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.

REFERENCES

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

V. V. MOSOLOV

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