2.3.2.33	[E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine + [acceptor protein]-L-threonine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-3-O-ubiquitinyl-L-threonine	
2.3.2.33	[E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine + [RCR-type E3 ubiquitin transferase]-L-cysteine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + [RCR-type E3 ubiquitin transferase]-S-ubiquitinyl-L-cysteine	
2.3.2.33	[RCR-type E3 ubiquitin transferase]-S-ubiquitinyl-L-cysteine + [acceptor protein]-L-threonine = [RCR-type E3 ubiquitin transferase]-L-cysteine + [acceptor protein]-3-O-ubiquitinyl-L-threonine