'proenzyme' definitions:

Definition of 'proenzyme'

(from WordNet)
noun
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 [syn: proenzyme, zymogen]

Definition of 'proenzyme'

From: GCIDE
  • proenzyme \pro"en*zyme\, n. [.] (Bioch.) Any one of a class of proteins that are converted, in the normal course of cellular metabolism, into one or more active enzymes; also called zymogen. The conversion usually is due to a specific cleavage of a peptide bond by another enzyme, or may be due to acid. [PJC]