A mother substance, or antecedent, of an enzyme or chemical ferment; -- applied to such substances as, not being themselves actual ferments, may by internal changes give rise to a ferment.
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
an enzymatically inactive protein that is converted to a proteolytic enzyme by the action of an activator
an inactive enzyme pre-cursor
an inactive form of an enzyme
A zymogen or a proenzyme, is an inactive enzyme precursor. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) for it to become an active enzyme. The biochemical change usually occurs in a lysosome where a specific part of the precursor enzyme is cleaved in order to activate it.