2.3.2.23	S-SUMOyl-[E1 SUMO-activating enzyme]-L-cysteine + [Ubc9]-L-cysteine	-	[E1 SUMO-activating enzyme]-L-cysteine + S-SUMOyl-[Ubc9]-L-cysteine	isoform Ubc9 is involved as E2 enzyme both in the ubiquitin and the ubiquitin-like SUMO pathway. Ubiquitin-like proteins SUMO-1, -2, and -3 interact with the same N-terminal region of the E2 conjugating enzyme Ubc9 with similar affinities	?	434336	
2.3.2.23	S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [E2 ubiquitin-conjugating enzyme]-L-cysteine	-	[E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine	-	?	434798	
2.3.2.23	S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [UBE2S]-L-cysteine	-	[E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[UBE2S]-L-cysteine	-	?	474410	
2.3.2.23	S-ubiquitinyl-[Uba1]-L-cysteine + [Ubc5a]-L-cysteine	-	[Uba1]-L-cysteine + S-ubiquitinyl-[Ubc5a]-L-cysteine	the E1 enzyme Uba1, the E2 enzyme UbcH5a, and the E3 enzyme TRIP12 are responsible for ubiquitylation of ubiquitin mutant G76V	?	434373	
2.3.2.23	[UBE2W]-S-ubiquitinyl-L-cysteine + [Josephin domain of ATXN3]-L-lysine	-	[UBE2W]-L-cysteine + [Josephin domain of ATXN3]-N6-ubiquitinyl-L-lysine	-	?	474815	
2.3.2.23	[ubiquitin-activating protein E1]-S-ubiquitinyl-L-cysteine + [ubiquitin carrier protein UbcH7]-L-cysteine	-	[ubiquitin-activating protein E1]-L-cysteine + [ubiquitin carrier protein UbcH7]-S-ubiquitinyl-L-cysteine	-	?	429046	
2.3.2.23	[ubiquitin-activating protein E1]-S-ubiquitinyl-L-cysteine + [ubiquitin-carrier-protein Ube2r]-L-cysteine	-	[ubiquitin-activating protein E1]-L-cysteine + [ubiquitin-carrier-protein Ube2r]-S-ubiquitinyl-L-cysteine	enzyme is capable of forming a thiolester bond with ubiquitin	?	429047	
2.3.2.23	[ubiquitin-activating protein Uba1a]-S-ubiquitinyl-L-cysteine + [ubiquitin-carrier-protein Ubc2b]-L-cysteine	-	[ubiquitin-activating protein Uba1a]-L-cysteine + [ubiquitin-carrier-protein Ubc2b]-S-ubiquitinyl-L-cysteine	-	?	429048	
2.3.2.23	[ubiquitin-activating protein Uba1]-S-ubiquitinyl-L-cysteine + [ubiquitin-carrier-protein Ubc2b]-L-cysteine	-	[ubiquitin-activating protein Uba1]-L-cysteine + [ubiquitin-carrier-protein Ubc2b]-S-ubiquitinyl-L-cysteine	-	?	429050	
2.3.2.23	[ubiquitin-activating protein Uba3]-S-ubiquitinyl-L-cysteine + [ubiquitin-carrier-protein Ubc12]-L-cysteine	-	[ubiquitin-activating protein Uba3]-L-cysteine + [ubiquitin-carrier-protein Ubc12]-S-ubiquitinyl-L-cysteine	-	?	429052