1.7.2.1	nitrite reductase (NO-forming)	-	
1.7.2.2	nitrite reductase (cytochrome; ammonia-forming)	-	
1.7.2.3	trimethylamine-N-oxide reductase	-	
1.7.2.4	nitrous-oxide reductase	-	
1.7.2.5	nitric oxide reductase (cytochrome c)	-	
1.7.2.6	hydroxylamine dehydrogenase	-	
1.7.2.7	hydrazine synthase	-	
1.7.2.8	hydrazine dehydrogenase	-	
1.7.2.9	hydroxylamine oxidase	-