A protein that may be converted into an enzyme.

Some proteins are synthesized as zymogens, which are enzymatically inactive precursors of proteolytic enzymes. Zymogens usually become activated by posttranslational modifications, such as cleavage in a particular peptide sequence.

An inactive precursor of an enzyme. For example, trypsin exists in the inactive form trypsinogen before it is converted to its active form, trypsin.

(n) 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 inactive precursor molecule which is transformed into its active form following cleavage by a protease.

An inactive enzyme precursor that is activated by proteolysis; a proenzyme.

(biochemistry) A proenzyme, or enzyme precursor, which requires a biochemical change (i.e. hydrolysis) to become an active form of the enzyme.