1.12.1.1	peroxidase	transferred to EC 1.18.99.1	
1.12.1.2	hydrogen dehydrogenase	-	
1.12.1.3	hydrogen dehydrogenase (NADP+)	-	
1.12.1.4	hydrogenase (NAD+, ferredoxin)	-	
1.12.1.5	hydrogen dehydrogenase [NAD(P)+]	-	
1.12.2.1	cytochrome-c3 hydrogenase	-	
1.12.5.1	hydrogen:quinone oxidoreductase	-	
1.12.7.1	ferredoxin hydrogenase	transferred to EC 1.18.99.1	
1.12.7.2	ferredoxin hydrogenase	-	
1.12.98.1	coenzyme F420 hydrogenase	-	
1.12.98.2	5,10-methenyltetrahydromethanopterin hydrogenase	-	
1.12.98.3	Methanosarcina-phenazine hydrogenase	-	
1.12.98.4	sulfhydrogenase	-	
1.12.98.B1	hydrogen:sulfur oxidoreductase	preliminary BRENDA-supplied EC number	
1.12.99.1	coenzyme F420 hydrogenase	transferred to EC 1.12.98.1	
1.12.99.2	coenzyme-M-7-mercaptoheptanoylthreonine-phosphate-heterodisulfide hydrogenase	deleted, this was a system comprising two enzymes and not a single enzyme, as was thought	
1.12.99.3	hydrogen:quinone oxidoreductase	transferred to EC 1.12.5.1	
1.12.99.4	N5,N10-methenyltetrahydromethanopterin hydrogenase	transferred to EC 1.12.98.2	
1.12.99.5	3,4-dihydroxyquinoline 2,4-dioxygenase	deleted, identical to EC 1.13.11.47	
1.12.99.6	hydrogenase (acceptor)	-