/ Dictionary / Index P proenzyme: Meaning and Definition of Find definitions for: pro•en•zyme Pronunciation: (prō-en'zīm), [key] — n. Biochem. any of a group of proteins that are converted to active enzymes by partial breakdown, as by the action of an acid or other enzyme. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: proenzyme (Thesaurus) proem proestrus Related Content Daily Word Quiz: opulent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language