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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 It might be outdated or ideologically biased.



(also proferment, zymogen, preenzyme), an inactive precursor of enzymes. Proenzymes form during the biosynthesis of enzymes. They are converted into active enzymes following limited proteolysis. The fission of usually one of the peptide bonds of the proenzyme molecule, which results in a partial structural change in the molecule, leads to the formation of the enzyme’s active center. Many proteolytics that are present in animals and bacteria, as well as phospholipase, are synthesized as proenzymes. Typical proenzymes include pepsinogen, trypsinogen, and prothrombin. Proenzymes are biologically important because they inhibit premature enzymatic activity in those cells and tissues where there is enzyme biosynthesis.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The Company's novel proenzyme therapy is based on the science that enzymes stimulate biological reactions in the body, especially enzymes secreted by the pancreas.
According to the company, the data provides the strongest evidence that proenzymes could be an effective tool in the fight against metastatic cancer, the single biggest cause of patient death for sufferers.
Metalloproteinases inactivation is based on forming complexes which consist of active forms of MMP or some proenzymes and tissue inhibitor, complexes MMP-TIMP [35, 36].
Caspases are the 30-60 KDa proenzymes inside cells.
Thus MMPs are regulated in several ways: during gene expression, by the need for activation of latent proenzymes and by being bound to inhibitory molecules.
There are two distinct gelatinases of the MMPs family, MMP-2 and MMP-9, which are also found as proenzymes, produced by basal cells for physiologic control of hoof growth (FRENCH & POLLITT, 2004).
Proenzymes were activated immediately prior to use with p-aminophenylmercuric acetate (APMA 2mM for 1h at 37[degrees] C for MMP-2 and MMP-8, APMA 2mM for 2h at 37[degrees]C for MMP-1, and APMA 1mM for 1h at 37[degrees]C for MMP-9).
MASP1, MASP-2, and MASP-3 are synthesised as proenzymes with apparent molecular weights of 90 kDa, 74 kDa, and 94 kDa, respectively.
MMPs tend to be secreted as proenzymes that require activation to reveal their enzyme activity, and the action of many of them is also controlled by their interactions with other proteins called 'TIMPs'--tissue inhibitors of metalloproteinases.
Caspases are present as proenzymes that are cleaved and activated during apoptosis, of which caspase-3 acts as an apoptotic executor.
They are then cleaved upon release from the secretory pathway to become proenzymes (1).