Type: Term Pronunciation: nū′klē-ō-sī′dās-ĕz Definitions: 1. Enzymes (particularly EC subgroup 3.2.2) that catalyze the hydrolysis or phosphorolysis of nucleosides, releasing the purine or pyrimidine base. Found on http://www.medilexicon.com/medicaldictionary.php?t=61284