1881, as a biochemical term, from German Enzym, coined 1878 by German physiologist Wilhelm Kühne (1837-1900), from Modern Greek enzymos "leavened," from en "in" (see en- (2)) + zymē "leaven" (see zymurgy). Related: Enzymotic.
type of immune-system enzyme found in tears, saliva, egg-whites, etc., 1922, named by its discoverer, Alexander Fleming (six years before he discovered penicillin), who coined it from lyso- "loosening, dissolving" + suffix from enzyme. So called because it attack bacteria cell walls.
1977, earlier retravirus (1974), from re(verse) tra(nscriptase) + connective -o- + virus. So called because it contains reverse transcriptase, an enzyme that uses RNA instead of DNA to encode genetic information, which reverses the usual pattern. Remodeled by influence of retro- "backwards."