EC 6.3 - Forming carbon-nitrogen bonds
To this subclass belong the amide synthases (EC 6.3.1), the peptide synthases (EC 6.3.2), enzymes forming heterocyclic rings (EC 6.3.3), enzymes using glutamine as amido-N-donor (EC 6.3.5) and a few others (EC 6.3.4).
Acid—ammonia (or amine) ligases (amide synthases)
Acid—amino-acid ligases (peptide synthases)
Other carbon—nitrogen ligases
Carbon—nitrogen ligases with glutamine as amido-N-donor