5.3.99.2	Ba2+	increase in activity	
5.3.99.2	Ca2+	half maximal effective concentration at 0.4 mM, 1.5fold increase in activity	
5.3.99.2	Mg2+	-	
5.3.99.2	Mg2+	half maximal effective concentration at 0.05 mM, 1.5fold increase in activity, Mg2+ increases the affinity for glutathione	
5.3.99.2	Sr2+	increase in activity