Reaction catalyzed by E1 SAMP-activating enzyme (6.2.1.55)

	[SAMP]-Gly-Gly-AMP	+		[E1 SAMP-activating enzyme]-L-cysteine	=			+		AMP
	[SAMP]-Gly-Gly-AMP	+		[E1 SAMP-activating enzyme]-L-cysteine	=		S-[[SAMP]-Gly-Gly]-[[E1 SAMP-activating enzyme]-L-cysteine]	+		AMP