Proenzyme (Noun)
Meaning
Any of a group of compounds that are inactive precursors of enzymes and require some change (such as the hydrolysis of a fragment that masks an active enzyme) to become active.
Classification
Nouns denoting substances.
Examples
- The proenzyme is converted into an active enzyme through a process of proteolytic cleavage, which removes a fragment that blocks the active site.
- Pepsinogen is a proenzyme that is secreted by the chief cells in the stomach lining and is activated to pepsin in the acidic environment of the stomach.
- The activation of a proenzyme often involves the removal of a peptide fragment that inhibits the enzyme's activity.
- Trypsinogen is a proenzyme produced in the pancreas that is converted into the active enzyme trypsin in the small intestine.
- The proenzyme is stored in an inactive form until it is needed, at which point it is activated through a series of biochemical reactions.