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(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.

References in periodicals archive ?
In the present work we describe a convenient, rapid, and sensitive method for detection of BACE-1 activity in biological samples, based on immunocapture with a specific BACE-1--binding antibody and a sensitive 2-step detection method based on activation of an engineered proenzyme.
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.
Within the duodenum, enterokinase converts trypsinogen to trypsin, and then active trypsin facilitates the conversion of the other pancreatic proenzymes to the active form.
The most plausible explanation is that mild acute pancreatitis is associated with a defect in the intracellular compartmentation of proenzymes in acinar cells and damaged pancreatic vasculature.
PRP involves the use of two pancreatic proenzymes, chymotrypsinogen and trypsinogen, which are enzymes in their inactive form.
They are then cleaved upon release from the secretory pathway to become proenzymes (1).
Caspases are present as proenzymes that are cleaved and activated during apoptosis, of which caspase-3 acts as an apoptotic executor.
UCB gelatinases are MMPs circulating as latent proenzymes in zymogenic activatable isoforms.
2+] dependence, and p-aminophenyl-mercuric acetate activation (data not shown) identified the plasma gelatinases as fibroblast-derived proMMP-2 and neutrophil-derived proMMP-9, circulating as latent activatable proenzymes.
Modified proenzymes as artificial substrates for proteolytic enzymes: a colorimetric assay of bacterial collagenase and matrix metal loproteinase activity using modified pro-urokinase.
Trypsin is produced in the exocrine pancreas as two major proenzymes, trypsinogen-1 (cationic) and trypsinogen-2 (anionic), which typically are activated in the duodenum by enterokinase to trypsin-1 and trypsin-2, respectively.