6.5.1.2	Ca2+	60% as active as Mg2+ in activation as reported in one study, no activity in another	1909, 1910	
6.5.1.2	K+	stimulates at low concentrations	1909	
6.5.1.2	Mg2+	optimal concentration: 1-3 mM	1909, 1910	
6.5.1.2	NH4+	stimulates at low concentrations	1909	
6.5.1.2	Zn2+	slight activation	1909, 1910	
6.5.1.2	K+	-	1910	
6.5.1.2	K+	stimulates	1910	
6.5.1.2	Mg2+	requires divalent cations, Mn2+ or Mg2+	1909, 1910, 1971	
6.5.1.2	Mn2+	activation at 0.2-1.0 mM, inhibition at higher concentration	1910	
6.5.1.2	Mn2+	requires divalent cations, Mn2+ or Mg2+	1909, 1910, 1971