2.7.7.44	Ca2+	36% of the activation with Mg2+	645282	
2.7.7.44	Co2+	40% of the activation with Mg2+	645282	
2.7.7.44	Mg2+	-	670505	
2.7.7.44	Mg2+	best fulfills the requirement for a divalent cation, maximal activity of forward reaction at a Mg2+/UTP ratio of 2:1. In the reverse reaction below 5 mM diphosphate, a Mg2+:diphosphate ratio of approximately 1:1 gives optimal activity, excess of Mg2+ is inhibitory	645282	
2.7.7.44	Mg2+	maximum activity in the presence of Mg2+. 20 mM used in assay conditions	760379	
2.7.7.44	Mg2+	required	645283	
2.7.7.44	Mn2+	can substitute for Mg2+ in either the forward or the reverse direction, 53% of the activation with Mg2+, excess of Mn2+ inhibits the reaction in both directions	645282	
2.7.7.44	Zn2+	37% of the activation with Mg2+	645282