Reaction catalyzed by (E3-independent) E2 ubiquitin-conjugating enzyme (2.3.2.24)

	[ubiquitin-carrier protein E2]-S-ubiquitinyl-L-cysteine	+			=		[ubiquitin-carrier protein E2]-L-cysteine	+		[histone H3]-N6-ubiquitinyl-L-lysine
	[ubiquitin-carrier protein E2]-S-ubiquitinyl-L-cysteine	+		[histone H3]-L-lysine	=		[ubiquitin-carrier protein E2]-L-cysteine	+		[histone H3]-N6-ubiquitinyl-L-lysine