2.5.1.6	Ca2+	0.02 mM stimulates activity	685392	
2.5.1.6	Co2+	-	639056	
2.5.1.6	Co2+	0.02 mM stimulates activity	685392	
2.5.1.6	Co2+	can replace Mg2+ with a lower relative activity, S-adenosylmethionine synthetase B	639048	
2.5.1.6	Co2+	can replace Mg2+ with lower relative activity	639048	
2.5.1.6	Co2+	for maximal activation the cation concentration must be at least equal to ATP concentration	639045	
2.5.1.6	Co2+	high activity in the presence of 20 mM Zn2+	738285	
2.5.1.6	Cs+	-	639056	
2.5.1.6	K+	-	639040, 639056, 673793, 674742, 675169, 675572, 676135, 676290, 676530	
2.5.1.6	K+	0.2 mM stimulates activity	685392	
2.5.1.6	K+	absolute requirement, cannot be replaced by Na+	639054	
2.5.1.6	K+	activation at 25-50 mM	639039	
2.5.1.6	K+	both Mg2+ and K+ required for full activity	639041	
2.5.1.6	K+	bound by G49	673389	
2.5.1.6	K+	enhances Kcat and decrees Km values for both substrates	639074	
2.5.1.6	K+	half-maximal activation at 25 mM KCl	727832	
2.5.1.6	K+	monovalent cations required for optimal activity, 50 mM K+ sufficient for full activity, can be replaced by NH4+ but not by Na+	639063	
2.5.1.6	K+	required	737471	
2.5.1.6	K+	slight activation	706910	
2.5.1.6	Li+	-	639056	
2.5.1.6	Mg2+	-	639040, 639057, 639058, 658062, 660154, 671563, 672360, 673398, 673793, 674245, 674278, 674742, 675169, 675572, 676135, 676290, 676530	
2.5.1.6	Mg2+	absolute requirement	639046, 639074	
2.5.1.6	Mg2+	absolute requirement, cannot be replaced by Mn2+	639054	
2.5.1.6	Mg2+	absolutely dependent upon the presence of Mg2+, suggesting that a Mg2+-ATP complex functions as substrate. Maximal activity is obtained at a Mg2+ concentration of 20 mM	728983	
2.5.1.6	Mg2+	both Mg2+ and K+ required for full activity	639041	
2.5.1.6	Mg2+	cannot be replaced by Ca2+	639066	
2.5.1.6	Mg2+	cation concentration must be at least equal to ATP concentration for maximal activity	639045, 639056	
2.5.1.6	Mg2+	maximal activation at 40 mM	639048	
2.5.1.6	Mg2+	Mg2+ in excess of that bound to ATP and EDTA is required for optimal activity	639052	
2.5.1.6	Mg2+	no activity is detectable in the absence of Mg2+, and maximal activity is observed at 10 mM MgCl2 when ATP is present at 5 mM, indicating that MgATP is probably the true substrate	727832	
2.5.1.6	Mg2+	optimal concentration at 10-20 mM	639039	
2.5.1.6	Mg2+	required	737471, 737689	
2.5.1.6	Mg2+	required for activity	685392	
2.5.1.6	Mg2+	S-adenosylmethionine synthetase A is absolutely dependent upon the presence of Mg2+, suggesting that a Mg-ATP complex functions as substrate. Maximal activity is obtained at an Mg2+ concentration of 40 mM with 10 mM ATP. 30% of the maximal reaction rate is observable at equimolar concentrations of ATP and Mg2+ (10 mM)	639048	
2.5.1.6	Mg2+	S-adenosylmethionine synthetase B is absolutely dependent upon the presence of Mg2+, suggesting that a Mg-ATP complex functions as substrate. Maximal activity is obtained at an Mg2+ concentration of 40 mM with 10 mM ATP. 30% of the maximal reaction rate is observable at equimolar concentrations of ATP and Mg2+ (10 mM)	639048	
2.5.1.6	Mg2+	strictly dependent on divalent cations with maximum activity at 5mM and Mg2+ fully replaceable by Mn2+ or Co2+ salts	639063	
2.5.1.6	Mg2+	the enzyme requires Mn2+ or Mg2+, which are equally active, bound by D17 and D289	673389	
2.5.1.6	Mg2+	the enzyme requires two divalent metal ions in the active site	737346	
2.5.1.6	Mg2+	up to 20% activation	706910	
2.5.1.6	Mn2+	-	639040, 639056	
2.5.1.6	Mn2+	can partially replace Mg2+ in activation, inhibition in presence of Mg2+	639046	
2.5.1.6	Mn2+	can replace Mg2+ with a lower relative activity, S-adenosylmethionine synthetase A	639048	
2.5.1.6	Mn2+	can replace Mg2+ with a lower relative activity, S-adenosylmethionine synthetase B	639048	
2.5.1.6	Mn2+	can replace Mg2+ with lower relative activity	639048	
2.5.1.6	Mn2+	for maximal activation the cation concentration must be at least equal to ATP concentration	639045	
2.5.1.6	Mn2+	optimal concentration at 2 mM	639039	
2.5.1.6	Mn2+	slight activiation	706910	
2.5.1.6	Mn2+	the enzyme requires Mn2+ or Mg2+, which are equally active	673389	
2.5.1.6	additional information	Ag+, Ca2+, Fe2+, and Cu2+ cannot substitue for Mg2+ or Mn2+	673389	
2.5.1.6	additional information	divalent cations are required for tripolyphosphatase activity	639056	
2.5.1.6	additional information	Mg2+, H2PO4-, NH4-, and NO3- have no significant effect on enzyme activity at 5 mM	685773	
2.5.1.6	additional information	no stimulatory effect by K+ has been observed even at high concentration (40 mM)	728983	
2.5.1.6	Na+	-	639056	
2.5.1.6	Na+	slight activation in absence of Mg2+	639046	
2.5.1.6	NH4+	-	639056	
2.5.1.6	NH4+	activity is dependent on both divalent Mg2+ or Mn2+ and monovalent cations NH4+ or K+	639040	
2.5.1.6	Ni2+	0.02 mM stimulates activity	685392	
2.5.1.6	Tl+	-	639056	
2.5.1.6	Zn2+	0.02 mM stimulates activity	685392	
2.5.1.6	Zn2+	66% of the activity with Mg2+ or Mn2+	673389	
2.5.1.6	Zn2+	highest activity in the presence of 20 mM Zn2+	738285