1.2.2.1	formate dehydrogenase (cytochrome)	-	
1.2.2.2	pyruvate dehydrogenase (cytochrome)	deleted, now covered by EC 1.2.5.1	
1.2.2.3	formate dehydrogenase (cytochrome-c-553)	transferred to EC 1.17.2.3	
1.2.2.4	carbon-monoxide dehydrogenase (cytochrome b-561)	deleted. Now classified as EC 1.2.5.3, aerobic carbon monoxide dehydrogenase	
1.2.2.B1	quinoprotein formaldehyde dehydrogenase (cytochrome b559/569)	preliminary BRENDA-supplied EC number	
1.2.2.B2	quinoprotein formaldehyde dehydrogenase (cytochrome cL)	preliminary BRENDA-supplied EC number