Enzymes that catalyze the cleavage of a carbon-nitrogen bond by means other than hydrolysis or oxidation. Subclasses are the AMMONIA-LYASES, the AMIDINE-LYASES, the amine-lyases, and other carbon-nitrogen lyases. EC 4.3.

Synonyms: Lyases, Carbon-Nitrogen, EC 4.3.-, Carbon-Nitrogen Lyases, Carbon Nitrogen Lyases